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Abstract: Loturco, I, Nunes, RFH, Lampert, RR, Silva, RLP, Hespanhol, JE, Novack, LF, Conde, JHS, Pereira, LA, and McGuigan, MR. Effects of two different low-volume resistance training programs applied during the off-season period on the speed-power performance of elite youth soccer players. . J Strength Cond Res 38(3): 571-576, 2024-The aim of this study was to analyze the changes in the speed-power performance of elite youth soccer players submitted to 2 different low-volume resistance training programs during the off-season period. Twenty under-17 players were randomly allocated to "traditional nonballistic" or "ballistic training" groups. Countermovement jump (CMJ), 20-m sprinting speed, and half-squat (HS) power tests were performed after the final match of the season (pretesting session) and at the beginning of the subsequent season (post-testing session), after 4 weeks of detraining. Between-group differences were assessed using a 2-way ANOVA with repeated measures followed by the Tukey's post hoc test. Performance variations were individually analyzed with the use of the "true changes" calculation. At post-tests, CMJ height and HS power remained unchanged ( p > 0.05) but similar and significant improvements in sprint speed were observed in both groups ( p < 0.05). However, notably, a larger number of players in the ballistic group exhibited "true changes" in HS power (i.e., 55 vs. 33%, compared with the traditional group, respectively). In conclusion, either low-volume ballistic or traditional resistance training schemes were able to increase sprint speed and maintain power output during a short interseason break in youth soccer players. Despite this apparent similarity, at the individual level, ballistic movements were more efficient at improving lower-body power. Practitioners can use the strategies described here to improve the sprint and power performance of soccer players during short periods of soccer-specific training cessation., (Copyright © 2023 National Strength and Conditioning Association.)

Abstract: Harrison, PW, James, LP, Jenkins, DG, McGuigan, MR, Holmberg, PM, and Kelly, VG. The effects of low-load squat jump and maximal isometric priming exercise on muscular performance and perceptual state. J Strength Cond Res 38(1): 1-9, 2024-The aim of this study was to examine responses at 3 and 27 hours after low-load jump squat (LL) and maximal isometric half-squat (ISO) priming stimuli. Fifteen resistance-trained males performed LL (4 × 3 at 20% 1 repetition maximum [1RM]), ISO (4 × 3 seconds), and control (CON) activities (standardized warm-up) in a randomized and counterbalanced order. Countermovement jump (CMJ) and isometric midthigh pull tests were conducted to assess performance changes after priming and CON activities. No clear changes in CMJ measures were found after priming activities compared with CON. However, small effect size improvements were found after priming stimuli completed on the same day. A 2.9% decrease in concentric phase duration (CI = 0.3-5.9, p = 0.333, Cliff's delta = -0.156) and a 9.1% increase in RSImod (CI = 0.2-12.3, p = 0.151, Cliff's delta = -0.218) occurred at 3 hours after LL compared with CON. Braking phase duration (CI = 0.8-10.6, p = 0.333, Cliff's delta = -0.213) was 2.9% shorter at 3 hours after ISO compared with CON. No clear changes in isometric peak force occurred after priming activities compared with CON. Additionally, questionnaires were completed to assess perceptual state and perceived effectiveness of the priming stimulus to influence performance. An increase in the "effect of activity" was perceived at 3 hours after LL and ISO (p = 0.013-0.044, Cliff's delta = 0.578-0.6) and at 27 hours after ISO (p = 0.99, Cliff's delta = 0.173) compared with CON. An increase in "muscular heaviness" was also reported at 3 hours after ISO compared with CON (p = 0.199, Cliff's delta = 0.320). The collective findings suggest limited benefits over the day after LL and ISO priming stimuli. However, as there was substantial variation in individual responses, the relative nature of priming responses should be considered when prescribing similar strategies in practical environments., (Copyright © 2023 National Strength and Conditioning Association.)

Abstract: Harrison, PW, Kelly, VG, Jenkins, DG, McGuigan, MR, Holmberg, PM, and James, LP. Does moderate-load priming activity influence maximal upper-body performance and perceptual state?. J Strength Cond Res 37(11): e581-e587, 2023-The results of previous research indicate that resistance exercise "priming" may improve strength-power measures within 48 hours after their completion. Although researchers have primarily examined performance responses after lower-body priming stimuli, investigations examining the effects of upper-body resistance priming exercises are presently limited. Therefore, the aim of this study was to examine upper-body pushing and pulling performance in addition to perceptual responses 3 and 27 hours after moderate-load (ML) upper-body resistance priming exercise. Fourteen resistance-trained men were assigned to complete ML priming (4 × 3 bench press and bench pull at 65% 1RM [repetition maximum]) and control (rest) protocols in a randomized and counterbalanced order. Peak velocity during the bench throw and bench pull tests involving different loads (25, 50, and 75% 1RM) showed no practical change at 3 and 27 hours after the priming session (p = 0.216-0.99, Cliff's d = -0.041 to 0.225). Small effect size increases in perceptual measures ("physical feeling," "physical performance," "aggression" [p = 0.400-0.553, Cliff's d = 0.183-0.201], and "muscular heaviness" [p = 0.178, Cliff's d = 0.231]) were found at 3 hours postpriming. A moderate practical increase was observed in perceived "physical feeling" compared with control (p = 0.385, Cliff's d = 0.349) in addition to small effect size increases in perceived "physical performance" and "aggression" (Cliff's d = 0.243-0.290) at 27 hours after priming activities. These results indicate that upper-body strength-power changes within 27 hours after ML upper-body resistance exercise priming are not practically meaningful., (Copyright © 2023 National Strength and Conditioning Association.)

Abstract: Loturco, I, Grazioli, R, Veeck, F, Nakamura, FY, Inácio, M, Schons, P, Preissler, A, Pinto, RS, Pereira, LA, McGuigan, MR, and Cadore, EL. Effects of a short-term detraining period on the strength deficit and functional performance of highly trained soccer players. J Strength Cond Res 37(10): 2058-2063, 2023-The aim of this study was to examine the effects of a 4-week detraining period on the neuromuscular performance of highly trained soccer players. Pre and post detraining, 18 adult soccer players (age: 27 ± 4.9 years; height: 180.2 ± 7.1 cm; body mass [BM]: 78.9 ± 7.6 kg) performed vertical jumps, 20-m linear sprints, curve sprint and change of direction speed tests, and a progressive loading test in the half-squat exercise with loads corresponding to 50, 100, and 150% of the players' BM to assess the peak-force (PF), mean power (MP), and strength-deficit (SDef). Pre and post differences in the variables of interest were analyzed using paired t -tests and effect sizes (ES). No significant changes were detected for vertical jumping height and sprint times. Higher PF at 50 and 100% BM and lower SDef were shown when comparing pre- and postassessments (ES = 0.66, 0.68, 0.55; p = 0.018, 0.016, and 0.046, respectively). The MP at 50 and 100% BM increased significantly after the detraining phase (ES = 0.56, 0.82; p = 0.049 and 0.007, respectively). The results indicate that these athletes were able to maintain and achieve satisfactory levels of performance after a short period of training cessation. Interestingly, some strength- and power-derived parameters improved significantly after short-term detraining, which may have important implications for training programs aimed at maximizing speed and power performance. It is recommended that coaches test their players not only at the beginning but also at the end of the season, to better evaluate variations in performance and thus create more efficient and tailored training strategies., (Copyright © 2023 National Strength and Conditioning Association.)

Abstract: Loturco, I, McGuigan, MR, Freitas, TT, Bishop, C, Zabaloy, S, Mercer, VP, Moura, TBMA, Arruda, AFS, Ramos, MS, Pereira, LA, and Pareja-Blanco, F. Half-squat and jump squat exercises performed across a range of loads: differences in mechanical outputs and strength deficits. J Strength Cond Res 37(5): 1052-1056, 2023-The aim of this study was to compare the peak force (PF), peak power (PP), and peak velocity (PV) outputs produced during half-squat (HS) and jump squat (JS) exercises executed at 20, 40, 60, and 80% of 1 repetition maximum (1RM) in the HS (HS 1RM) and to compute and compare the strength deficit (SDef) achieved in these exercises across these loads. Twenty-four national rugby union players (age: 25.7 ± 3.6 years) performed HS 1RM and a progressive loading test in the HS and JS exercises. The PF, PP, and PV values were obtained in all loads for both exercises, and the SDef was calculated as the percentage difference between the PF at distinct relative intensities and the PF at HS 1RM. The differences in HS and JS variables were determined using an analysis of variance with repeated measures. Higher PF, PP, and PV outputs were generated in the JS in comparison with the HS exercise ( p < 0.05); moreover, the SDef magnitudes were significantly lower in the JS ( p < 0.01), for all loading conditions. Importantly, the differences in SDef, and as a consequence, PF, PP, and PV decreased progressively with increasing load. Overall, the loaded JS exhibited increased levels of PF, PP, and PV and reduced levels of SDef when compared to the traditional HS performed across a range of loads. The JS is indicated to reduce the SDef and improve the athletes' ability to apply force at higher velocities. Nevertheless, with heavier loads (i.e., ≥80% HS 1RM), its potential advantages and effectiveness may be seriously compromised., (Copyright © 2022 National Strength and Conditioning Association.)

Abstract: Spence, AJ, Helms, ER, Sousa, CA, and McGuigan, MR. Range of motion predicts performance in National-level New Zealand male powerlifters. J Strength Cond Res 37(1): 123-128, 2023-Previous research established that male powerlifters have less range of motion (ROM) in several movements about the shoulder and hip compared with sedentary male subjects. It is unclear if these differences in ROM are related to strength, training type, and years of training experience or if individuals with less ROM have a better propensity to gain strength. The purpose of this study was to compare strength and ROM in male powerlifters and recreationally strength-trained male subjects and to determine if ROM would be an effective predictor of strength in these groups. Twelve powerlifters and 12 recreationally strength-trained control subjects completed 1 repetition maximum (1RM) squat and bench press testing. In a subsequent session, active ROM was measured, and velocity data were collected during submaximal squat repetitions. There was no significant difference (p > 0.05) between the groups for age, height, body mass, training experience, and training frequency. Powerlifters had significantly greater (p ≤ 0.05) training duration and absolute squat and bench press 1RM. Powerlifters had significantly less shoulder extension and horizontal abduction, and hip flexion, extension, and adduction than recreationally strength-trained men. Significant negative relationships were found between 2-lift Wilks score (body mass relative strength) and shoulder extension and horizontal abduction, as well as hip flexion and extension. In powerlifters, significant negative relationships were found between competition Wilks score, shoulder extension, and hip flexion. Because these relationships correspond to the bottom position of the squat and bench press, it may be best to ensure that shoulder extension and hip flexion remain sufficient to achieve competition depth., (Copyright © 2021 National Strength and Conditioning Association.)

Abstract: Spence, A-J, Helms, ER, and McGuigan, MR. Stretching practices of International Powerlifting Federation unequipped powerlifters. J Strength Cond Res 36(12): 3456-3461, 2022-Stretching practices in powerlifters. The purpose of this study was to provide insight into the stretching practices of competitive powerlifters. Powerlifters ( n = 319) from 51 countries completed a self-reported online survey on stretching practices. Subjects had (mean ± SD , median, and interquartile range) 7.7 ± 6.1, 6, and 6 years of general resisting training, 4.4 ± 4.5, 3, and 3 years of strength specific training, and been competing in powerlifting for 3.0 ± 3.7, 2, and 2 years with the average Wilks score being 366.4 ± 52.2, 365, and 60. Analysis by sex and competitive standard was conducted. More than 50% (52.4%) of subjects ( n = 167) reported stretching; of those, 84.4% performed static stretches, and 90.4% performed dynamic stretches. Stretching was performed before resistance training by 77.8%, after resistance training by 43.7%, and 53.9% stretched independent of resistance training. Powerlifters who performed static stretches before training did an average of 6.72 ± 10.31, 5, and 8 repetitions per stretch and held those stretches for an average of 30.8 ± 31.4, 20, and 15 seconds; 90.1% also performed dynamic stretches. Powerlifters who performed static stretches after or independent of training did an average of 4.1 ± 4.2, 2, and 9 repetitions per stretch and held those stretches for an average of 42.9 ± 30.8, 30, and 33 seconds. The majority of powerlifters (66.9%) programmed stretching themselves, whereas only 10.2% had stretching programmed by their coach. These data will inform athletes and coaches about the prevalence and characteristics of current stretching practices in powerlifters., (Copyright © 2022 National Strength and Conditioning Association.)

Abstract: Loturco, I, Pereira, LA, Reis, VP, Zanetti, V, Bishop, C, and Mcguigan, MR. Traditional free-weight vs. variable resistance training applied to elite young soccer players during a short preseason: Effects on strength, speed, and power performance. J Strength Cond Res 36(12): 3432-3439, 2022-Maximizing the neuromuscular capacities of players is a critical challenge during short soccer preseasons. This study compared the effects of 2 strength-power training regimes, on the strength, speed, and power performance of elite young soccer players during a 4-week preseason. Twenty-five under-20 players from the same club were pair matched in 2 training groups as follows: traditional training group (TTG) ( n = 13), athletes performed half-squat (HS) and jump-squat (JS) exercises as traditionally prescribed, and elastic band (EB) group (EBG) ( n = 12), athletes performed HS and JS with EB attached to the barbell. Vertical jump height, 20-m sprint velocity, change of direction (COD) speed, HS and JS power, and 1 repetition maximum (1RM) in the HS were assessed before, after 2-week, and after 4-week of training. A two-way analysis of variance with repeated measures was used to assess the effects of both training protocols over the experimental period. Both strategies were effective for significantly improving HS and JS power (effect sizes [ESs] = 1.00-1.77), HS 1RM (ES = 1.68 and 1.51 for TTG and EBG, respectively), vertical jumping ability (ES = 0.37-0.65), and COD speed (ES = 0.81 and 0.39 for TTG and EBG, respectively), when comparing premeasures and postmeasures. By contrast, both TTG and EBG failed to increase 20-m sprint velocity (ES ranging between -0.54 and 0.23). In conclusion, both training schemes were able to improve the strength and power performance but not the sprint capacity of young soccer players. To accelerate strength gains over very-short time periods (i.e., 2 weeks), variable resistance training may be advantageous. Conversely, to optimize power adaptations in ballistic exercises across a similar time period, traditional free-weight training may be preferred., (Copyright © 2022 National Strength and Conditioning Association.)

Abstract: Loturco, I, McGuigan, MR, Rodríguez-Rosell, D, Pereira, LA, and Pareja-Blanco, F. A novel strategy to determine the 1-repetition maximum in the jump squat exercise. J Strength Cond Res 36(8): 2330-2334, 2022-This study aimed to determine the maximum relative load of the half-squat (HS; i.e., % HS 1-repetition maximum [1RM]) that can be used in its ballistic variation, namely, the jump squat (JS) exercise, and to examine whether this reference value varies in subjects with different strength levels. In total, 186 elite athletes from 10 distinct sport disciplines participated in this study. A progressive loading test up to HS 1RM was performed during the competitive phase of the season for all athletes. Mean propulsive velocity and propulsive phase duration were also assessed during the 1RM test. Athletes were divided into 3 distinct subgroups: "low," "middle," and "high" strength levels, based on their relative HS 1RM values (kg·kg -1 ). A 1-way analysis of variance was used to compare the variables assessed between the groups. Significance level was set at p < 0.05. The high group demonstrated the highest relative HS 1RM values, followed by the middle and low groups (all p < 0.05). No significant differences were observed between the groups for the remaining variables ( p > 0.05). It was observed that at 86.0 ± 5.4% 1RM, the full concentric action can already be considered as entirely propulsive in the HS exercise for all subjects, independent of their strength levels. Therefore, this relative strength value may be used as a reference for the 1RM in the JS exercise., (Copyright © 2020 National Strength and Conditioning Association.)

Abstract: Spence, A-J, Helms, ER, and McGuigan, MR. Range of motion is not reduced in national-level New Zealand female powerlifters. J Strength Cond Res 35(10): 2737-2741, 2021-Some research suggests male powerlifters have less range of motion (ROM) in several directions about the shoulder and hip compared with sedentary men. In addition, those differences may be more pronounced in groups with higher strength levels and more years of experience. However, there is no information on ROM in female powerlifters. The purpose of this study was to evaluate single-joint ROM in competitive female powerlifters and determine whether single-joint ROM would be an effective predictor of strength in this population. Twelve female powerlifters and 12 female recreationally trained age-matched controls attended one testing session. Subjects reported their years of training experience, frequency, and average duration of training sessions. Active ROM measurements were collected at the shoulder, hip, and knee, using goniometry. There was no significant difference (p > 0.05) between groups for age, height, body mass, training experience, and training frequency. Powerlifters reported significantly greater (p ≤ 0.05) training durations than recreationally trained women. Powerlifters had significantly greater shoulder horizontal abduction on the right side (p = 0.022, g = 0.97), but no other ranges were significantly different between groups, and no ranges were significantly related to strength. Powerlifting does not seem to affect shoulder, hip, or knee ROM differently than recreational resistance training in women. Single-joint ROM was not an effective predictor of strength in female powerlifters., (Copyright © 2021 National Strength and Conditioning Association.)

Abstract: Watkins, CM, Storey, A, McGuigan, MR, Downes, P, and Gill, ND. Horizontal force-velocity-power profiling of rugby players: A cross-sectional analysis of competition-level and position-specific movement demands. J Strength Cond Res 35(6): 1576-1585, 2021-Speed and acceleration are crucial to competitive success in all levels of rugby union. However, positional demands affect an athlete's expression of force and velocity during the match. This study investigated maximal sprint performance and horizontal force-velocity (FV) profiles in 176 rugby union players participating in amateur club, professional, and international competitions. Rugby players were divided into 5 positional groups: tight-5 forwards (n = 63), loose forwards (n = 35), inside backs (n = 29), midbacks (n = 22), and outside (n = 27) backs. Sprint performance was averaged across 2 trials of a maximal 30-m sprint, separated by a 3-minute rest. The results demonstrated differences in sprint performance and FV profile characteristics across competitions and positional groups. Specifically, both international and professional players possessed significantly faster split times and superior FV profiles than club players (p < 0.01; effect size [ES]: 0.22-1.42). International players were significantly faster across 0-10 m than professional players (p = 0.03; ES: 0.44-0.47), whereas professional players had faster 10-20 m times (p = 0.03; ES: 0.37-0.41) and a more force-dominant profile (p < 0.01; ES: 0.71-1.00). Across positions, split times decreased and maximal velocity characteristics increased in proportion with increasing positional number, with outside backs being the fastest (ES: 0.38-2.22). On the other hand, both forwards groups had more force-dominant profiles and average sprint momentum across all distances than all backs positions. Interestingly, loose forwards had a more forceful profile and slower 10-, 20-, and 30-m split times but similar maximal velocity characteristics to inside backs, highlighting unique positional demands and physical attributes., (Copyright © 2021 National Strength and Conditioning Association.)

Abstract: Watkins, CM, Storey, A, McGuigan, M, and Gill, ND. Implementation and efficacy of plyometric training: Bridging the gap between practice and research. J Strength Cond Res 35(5): 1244-1255, 2021-Plyometric training is an effective method for improving speed and acceleration. However, a gap seems to exist between research recommendations and practitioner's actual programs. Some reports suggest as many as 400 jumps per session, while anecdotally some strength and conditioning coaches are using as few as 15-40 jumps even with elite athletes. Thus, the purposes of this study were to obtain a clearer understanding of the practitioner's perspective on plyometric training strategies as compared to literary recommendations and to compare any trends across competition level or sport categories. An integrative mixed-methods model was used. Globally, 61 strength and conditioning practitioners completed an anonymous online survey, containing 5 sections: 1. Sport and coaching background information, 2. Plyometric training focus, 3. Periodization strategy, 4. Plyometric program details, and 5. Efficacy of plyometrics for sport performance. Questions included yes/no, multiple choice, Likert scale, percentage-based, and open-ended questions. The majority (70.5%) of respondents reported regularly implementing plyometric training and overwhelmingly (96.7%) reported positive athlete feedback surrounding its perceived efficacy. Findings confirmed that many practitioners regularly use significantly lower session volumes than previous literary recommendations (p < 0.05). In addition, significant differences were noted in many program details across competition level and sport category including volume periodization, exercise choice, and plyometric intensity. Practitioners may want to reflect on these reported group differences when building training programs best suited for their athletes. Meanwhile, future research should consider these reported perspectives when formulating interventions in attempts of bridging the gap between practice and theory., (Copyright © 2021 National Strength and Conditioning Association.)

Abstract: Watkins, CM, Gill, ND, Maunder, E, Downes, P, Young, JD, McGuigan, MR, and Storey, AG. The effect of low-volume preseason plyometric training on force-velocity profiles in semiprofessional rugby union players. J Strength Cond Res 35(3): 604-615, 2021-Rugby union is a physically demanding and complex team sport requiring athletes across all positions to express speed and acceleration. Plyometrics can effectively improve speed profiles by enhancing both force- and velocity-(FV) characteristics; however, the optimal dose and exercise direction for trained athletes is still relatively unknown. Therefore, the aim of this investigation was to determine the efficacy of a low-dose, directionally specific plyometric training program for improving speed profiles in semiprofessional rugby players. Players were randomly allocated to one of 2 plyometric training groups that performed low-volume (40-60 ground contacts per session) plyometrics twice weekly, or a control group that did not participate in any plyometric training. The 2 training groups underwent reverse back-to-back three-week vertically and horizontally focused plyometric training programs, with a 12-day washout. Body composition, aerobic capacity, and sprint performance (10-, 20-, 30-m split time, horizontal FV profile) were measured. During the intervention, HV-1 (horizontal/vertical training group 1) improved sprint performance (n = 12; ∆30 m = -0.020 seconds; p = 0.038), VH-2 (vertical/horizontal training group 2) maintained sprint performance (n = 8; ∆30 m = +0.049 seconds; p = 0.377), and the control group progressively declined in sprint performance (n = 12; ∆30 m = +0.071; p = 0.019). In addition, vertical plyometrics may preferentially benefit secondary acceleration (∆10-20 m split time: -0.01 seconds; p = 0.03) and many force-oriented FV profile characteristics. Correlational analyses (r2 = -0.568 to 0.515) showed sprint improvements were hindered in athletes with lower initial aerobic fitness, suggesting accumulated fatigue may have limited the magnitude of adaptation. Therefore, including low-volume plyometric training may be beneficial for improving sprint profiles or attenuating decrements realized during periods of high-volume sport-specific training., (Copyright © 2020 National Strength and Conditioning Association.)

Loturco, I, McGuigan, MR, Suchomel, T, Freitas, TT, Rodríguez-Rosell, D, Pereira, LA, and Pareja-Blanco, F. Determining the one repetition maximum in the ballistic bench press exercise. J Strength Cond Res 34(12): 3321-3325, 2020-The purpose of this study was to determine the relative load (% of one repetition maximum [1RM]) at which the concentric action becomes entirely propulsive in the bench press (BP) exercise and verify whether this relative load varies between athletes with different strength levels. Twenty-eight professional athletes (Olympic boxers, professional mixed martial arts fighters, and elite rugby players) performed a progressive loading test up to their 1RM in the BP exercise (BP-1RM). Athletes were ordered according to their relative strength values and equally divided into 2 different groups: "low" (≤1.34) and "high" (≥1.38) strength levels. An independent t-test was used to compare the variables between groups. Significance level was set at p < 0.05. No significant differences were observed between the groups for the mean propulsive velocity attained at 1RM and for the maximum load that required braking action during the execution of the traditional BP exercise (effect size = 0.27 and 0.15, respectively; p > 0.05). Our results revealed that at 80% 1RM the concentric action can already be considered as 100% propulsive in the BP exercise. Importantly, this occurrence was independent of strength level. Therefore, this relative strength measure (i.e., 80% BP-1RM) may be used as a reference for the 1RM in the BP throw.

Whitehead, MT, Scheett, TP, McGuigan, MR, and Martin, AV. A comparison of the effects of short-term plyometric and resistance training on lower-body muscular performance. J Strength Cond Res 32(10): 2743-2749, 2018-The purpose of this study was to compare effects of short-term plyometric and resistance training on lower-body muscular performance. A convenience sample of 30 male subjects aged 21.3 ± 1.8 years (height, 177.3 ± 9.4 cm; mass, 80.0 ± 2.6 kg; body fat, 16.1 ± 1.2%) participated in this investigation. Participants were grouped, and they participated in progressive plyometric (PLT) or resistance training (SRT) twice per week for 8 consecutive weeks or a control (CNT) group that did not participate in any training. Performance tests were administered before and after the training period, and it included measures of high-speed muscular strength (standing long jump, vertical jump), low-speed muscular strength (1-repetition maximal back squat), running speed (20-m sprint), and running agility (505 agility test). Analysis of variance followed by post hoc analyses was performed to determine significant differences between the groups. Significance set at p ≤ 0.05 for all analyses. Significant improvements were observed in the PLT group for standing long jump, vertical jump, and 1-repetition maximal back squat compared with the CNT group and for vertical jump as compared with the SRT group. Significant improvements were observed in the SRT group 1-repetition maximal back squat compared with the CNT group. There were no differences observed between any of the groups for the 20-m sprint or the 505 agility test after the training. These data indicate that 8 weeks of progressive plyometric training results in improvements in parameters of high-speed and low-speed muscular strength with no appreciable change in speed or agility. Additionally, the improvement in low-speed muscular strength observed from 8 weeks of progressive plyometric training was comparable to the results observed from 8 weeks of progressive strength training.

Pritchard, HJ, Barnes, MJ, Stewart, RJC, Keogh, JWL, and McGuigan, MR. Short-term training cessation as a method of tapering to improve maximal strength. J Strength Cond Res 32(2): 458-465, 2018-The aim of this study was to determine the effects of 2 different durations of training cessation on upper- and lower-body maximal strength performance and to investigate the mechanisms underlying performance changes following short-term training cessation. Eight resistance trained males (23.8 ± 5.4 years, 79.6 ± 10.2 kg, 1.80 ± 0.06 m, relative deadlift 1 repetition maximum of 1.90 ± 0.30 times bodyweight [BW]) each completed two 4-week strength training periods followed by either 3.5 days (3.68 ± 0.12 days) or 5.5 days (5.71 ± 0.13 days) of training cessation. Testing occurred pretraining (T1), on the final day of training (T2), and after each respective period of training cessation (T3). Participants were tested for salivary testosterone and cortisol, plasma creatine kinase, psychological profiles, and performance tests (countermovement jump [CMJ], isometric midthigh pull, and isometric bench press [IBP]) on a force plate. Participants' BW increased significantly over time (p = 0.022). The CMJ height and IBP peak force showed significant increases over time (p = 0.013, 0.048, and 0.004, respectively). Post hoc testing showed a significant increase between T1 and T3 for both CMJ height and IBP peak force (p = 0.022 and 0.008 with effect sizes of 0.30 and 0.21, respectively). No other significant differences were seen for any other measures. These results suggest that a short period of strength training cessation can have positive effects on maximal strength expression, perhaps because of decreases in neuromuscular fatigue.

Bridgeman, LA, McGuigan, MR, Gill, ND, and Dulson, DK. Relationships between concentric and eccentric strength and countermovement jump performance in resistance trained men. J Strength Cond Res 32(1): 255-260, 2018-The purpose of this study was to investigate the relationships between concentric and eccentric peak force (PF) and countermovement jump (CMJ) performance in resistance trained men. Subjects were 12 men (mean ± SD; age: 25.4 ± 3.5 years; height: 177.2 ± 4.5 cm; mass: 84.0 ± 10.1 kg). The men were tested for concentric and eccentric PF using the Exerbotics squat device. Subjects then completed 3 CMJs to allow for the calculation of peak power (PP), peak ground reaction force, and jump height (JH). Correlations between the variables of interest were calculated using Pearson product-moment correlation coefficients. A large relationship was found between absolute concentric PF and absolute CMJ PP (r = 0.66, p ≤ 0.05). Absolute eccentric PF had a very large relationship with absolute CMJ PP and CMJ JH (r = 0.74, p < 0.01 and r = 0.74, p < 0.001, respectively). In addition, absolute eccentric PF was found to have a moderate relationship with relative CMJ PP (r = 0.58, p ≤ 0.05). Relative eccentric PF was had a very large relationship with relative CMJ PP and CMJ JH (r = 0.73, p < 0.001 and r = 0.79, p < 0.001, respectively). Based on these findings, strength and conditioning coaches and athletes who wish to enhance CMJ performance may wish to include exercises, which enhance lower-body eccentric strength within their training.

The aim of this study was to use the Oslo Sports Trauma Research Center (OSTRC) Overuse Injury Questionnaire to record overuse injuries over a single season for a men's professional basketball team to (a) assess the prevalence and severity of overuse injuries and (b) determine the efficacy of this method in identifying overuse injuries in comparison with the team physiotherapist's detection of these injuries. Thirteen athletes from a men's professional basketball team participated in this study. The self-reported, OSTRC injury questionnaire was used to record overuse conditions of the ankle, knee, and lower back over an entire 24-week season. Standard time-loss injury registration methods were also used to record overuse conditions by the physiotherapist. Overuse injury rates per 1,000 hours of athlete exposure and average weekly prevalence of overuse injuries were calculated using the results of the questionnaire. A total of 183 overuse conditions were identified by the questionnaire, whereas only 28 overuse conditions were identified by the physiotherapist. The team's average weekly prevalence of all overuse conditions was 63% (95% confidence interval [CI]: 60-66), with the highest prevalence of injury affecting the lower back (25.9% [95% CI: 19.7-32.1]). The overuse injury rate per 1,000 hours of athlete exposure was 6.4. The OSTRC overuse injury questionnaire captures many more overuse injuries in basketball than standard time-loss methods. The prevalence of lower back injuries is higher than that previously reported in basketball. This additional method of overuse injury surveillance may more accurately quantify the overuse injury problem in basketball and aid earlier intervention and management of these conditions.

The aims of this study were (a) to investigate the acute effects of different drop jump (DJ) accentuated eccentric loading (AEL) protocols and (b) to investigate the effect of these AEL DJ protocols on subsequent countermovement jump (CMJ) performance. The subjects were 12 strength-trained athletes; initially, baseline CMJ performance was assessed and individual optimal DJ drop height identified. In subsequent weeks, subjects completed 1 set of 5 DJs with no additional load or an AEL of 10, 20, or 30% of their individual body mass (BM) using dumbbells to provide the extra load. After the AEL DJ protocols, 3 CMJs were completed after 2, 6, and 12 minutes rest. A generalized linear mixed model was used to investigate the effects of AEL load and time post-DJs on CMJ height, peak power, and ground reaction force. The 20% AEL condition resulted in greater CMJ height in comparison with all other conditions (p < 0.001). CMJ height was significantly greater after 2 and 6 minutes rest compared with 12 minutes (p < 0.001 and p ≤ 0.05 respectively). Greater peak power was also found during the CMJs after the 20% AEL condition compared with baseline, BM, and 10% AEL (p ≤ 0.05). In conclusion, 5 DJs with 20% AEL followed by a 2 minutes recovery period resulted in significant enhancement in CMJ height and peak power.

Bridgeman, LA, Gill, ND, Dulson, DK, and McGuigan, MR. The effect of exercise induced muscle damage after a bout of accentuated eccentric load drop jumps and the repeated bout effect. J Strength Cond Res 31(2): 386-394, 2017-Although previous studies have investigated exercise-induced muscle damage (EIMD) after a bout of unloaded drop jumps (DJs), none have investigated the effects of accentuated eccentric load (AEL) DJs on EIMD. The purpose of this study was to investigate the effects of 30 and 50 AEL DJs on strength, jump performance, muscle soreness, and blood markers. Eight resistance trained athletes participated in this study. In week 1, baseline countermovement jump (CMJ), squat jump (SJ), concentric and eccentric peak force (PF), creatine kinase, and muscle soreness were assessed. Subjects then completed 30 AEL DJs and baseline measures were retested immediately postintervention, 1, 24, and 48 hours later. Two weeks later, the subjects completed the same protocol with an increase in AEL DJ volume (50). Subjects' SJ height was reduced in week 1 compared with week 3, postintervention, 1, 24, and 48 hours later (ES = -0.34, -0.44, -0.38, and -0.40). Subjects' CMJ height was reduced in week 1 compared with week 3, postintervention, 1, and 24 hours later (ES = -0.37, -0.29, and -0.39). Concentric PF was reduced in week 1 compared with week 3, postintervention and 24 and 48 hours later (ES = -0.02, -0.23, and -0.32). Eccentric PF was reduced in week 1 compared with week 3, postintervention, 24, and 48 hours later (ES = -0.24, -0.16, and -0.50). In this sample, 30 AEL DJs attenuated the effects of EIMD following which 50 AEL DJs completed 2 weeks later.

Bridgeman, LA, McGuigan, MR, Gill, ND, and Dulson, DK. Test-retest reliability of a novel isokinetic squat device with strength-trained athletes. J Strength Cond Res 30(11): 3261-3265, 2016-The aim of this study was to investigate the test-retest reliability of a novel multijoint isokinetic squat device. The subjects in this study were 10 strength-trained athletes. Each subject completed 3 maximal testing sessions to assess peak concentric and eccentric force (N) over a 3-week period using the Exerbotics squat device. Mean differences between eccentric and concentric force across the trials were calculated. Intraclass correlation coefficients (ICCs) and coefficients of variation (CVs) for the variables of interest were calculated using an excel reliability spreadsheet. Between trials 1 and 2 an 11.0 and 2.3% increase in mean concentric and eccentric forces, respectively, was reported. Between trials 2 and 3 a 1.35% increase in the mean concentric force production and a 1.4% increase in eccentric force production was reported. The mean concentric peak force CV and ICC across the 3 trials was 10% (7.6-15.4) and 0.95 (0.87-0.98) respectively. However, the mean eccentric peak force CV and ICC across the trials was 7.2% (5.5-11.1) and 0.90 (0.76-0.97), respectively. Based on these findings it is suggested that the Exerbotics squat device shows good test-retest reliability. Therefore practitioners and investigators may consider its use to monitor changes in concentric and eccentric peak force.

Pritchard, HJ, Tod, DA, Barnes, MJ, Keogh, JW, and McGuigan, MR. Tapering practices of New Zealand's elite raw powerlifters. J Strength Cond Res 30(7): 1796-1804, 2016-The major aim of this study was to determine tapering strategies of elite powerlifters. Eleven New Zealand powerlifters (28.4 ± 7.0 years, best Wilks score of 431.9 ± 43.9 points) classified as elite were interviewed, using semistructured interviews, about their tapering strategies. Interviews were transcribed verbatim and content analyzed. Total training volume peaked 5.2 ± 1.7 weeks from competition while average training intensity (of 1 repetition maximum) peaked 1.9 ± 0.8 weeks from competition. During tapering, volume was reduced by 58.9 ± 8.4% while intensity was maintained (or slightly reduced) and the final weight training session was performed 3.7 ± 1.6 days out from competition. Participants generally stated that tapering was performed to achieve full recovery; that accessory work was removed around 2 weeks out from competition; and deadlifting takes longer to recover from than other lifts. Typically participants stated that trial and error, and changes based on "feel" were the sources of tapering strategies; equipment used and movements performed during tapering are the same as in competition; nutrition was manipulated during the taper (for weight cutting or performance aims); and poor tapering occurred when too long (1 week or more) was taken off training. These results suggest that athletes may benefit from continuing to strength train before important events with reduced volume and maintained intensity. Only exercises that directly assist sports performance should remain in the strength program during tapering, to assist with reductions in fatigue while maintaining/improving strength expression and performance.

There is a constant and necessary evolution of training and assessment methods in the elite contact sports; as is required to continually improve the physical qualities of these respective athletes to match the growing sport and position-specific performance demands. Our aim was to examine the differences between ballistic upper body performance profiles and maximum upper body strength of elite rugby union forwards and backs. Twenty semiprofessional male rugby union players (age = 21.1 ± 3.0 years; mass = 94.9 ± 9.7 kg) were assessed for maximum bench press strength (1RM bench press = 121.3 ± 21.8 kg) and maximum throw power (Pmax), force (Fmax), and velocity (V[Combining Dot Above]max) from an incremental relative load testing protocol (15, 30, 45, 60, and 75% 1RM). Player rankings were also included to identify individual strength and weaknesses. The forwards were moderately stronger (effect size [ES] = 0.96; p = 0.01), produced significantly greater Fmax (ES = 1.17-1.41; p = 0.01) and were more powerful (ES = 0.57-0.64; p < 0.43) than the backs. V[Combining Dot Above]max differences were trivial to small (ES = -0.32 to -0.65; p > 0.15). There were inherent differences in strength and Fmax between the forwards and backs most likely because of the physical demands of these respective positions. Improvements in upper body strength may in turn improve ballistic force and power production, but not necessarily velocity capabilities. From the Fmax and V[Combining Dot Above]max observations, the forwards seem to be more force dominant and the backs more velocity dominant. Pmax, Fmax, and V[Combining Dot Above]max may be used to highlight proficient and deficient areas in ballistic upper body performance; the individual rankings could be further used to identify and possibly rectify individual deficiencies.

This study investigated the relationship between vertical and horizontal measures in bilateral and unilateral countermovement jump, drop jump and squat jump (SJ), and sprinting speed and muscle architecture of both the vastus lateralis and gastrocnemius. Subjects (n = 17) completed a 30-m sprint test, muscle stiffness test; ultrasound measures, and a jump testing session. Measures of horizontal peak and mean force, in both bilateral and unilateral jumps, tended to have greater relationships to sprint speeds (R = 0.132-0.576) than peak and mean force in the vertical plane (R = 0.008-0.504). Vertical velocity variables also showed some large and very large correlations to sprint speed (R = 0.062-0.635). Unilateral measures of velocity tended to have larger correlations to sprint performance than their bilateral counterparts across all jump types and peak and mean velocity in SJ showed large and very large correlations to sprint speed (bilateral R = 0.227-0.635; unilateral 0.393-0.574). Few large correlations were shown between muscle stiffness measures of muscle architecture and kinetic and kinematic variables in either vertical or horizontal jumps. The present findings suggest that sport scientists and strength and conditioning practitioners concerned with the prognostic value of kinetic variables to functional movements such as sprint speed should also use horizontal jumps in addition to vertical jumps in testing and training.

The purpose of this study was to investigate the chronic effect of a contrast training program designed to elicit an acute short term enhancement (STE) effect during training. A matched pairs training study design was implemented with a contrast (STE affected) and complex (control) training group completing a seven week training intervention. Twenty subjects participated. The contrast training group completed training based on a preloading protocol that had previously been shown to induce an acute STE effect within the subject population. The control group completed the same volume and type of training in a complex training format. Changes in squat 4RM strength and kinetic and kinematic performance in vertical and horizontal countermovement jump (CMJ) and drop jump (DJ) were measured via a Force Plate. Differences between the experimental and control group in change of mean strength (effect size 0.03 ± 0.33), vertical DJ (effect size: contact time -0.22 ± 0.52; peak force 0.20 ± 0.30; mean force 0.30 ± 0.74) and horizontal DJ (effect size: contact time -0.47 ± 0.73; peak force 0.03 ± 0.36; mean force 0.13 ± 0.56) were not meaningful. However, differences in mean change of vertical and horizontal CMJ measures of force (effect size range 0.40 - 0.46 ± 0.37 - 0.63), vertical CMJ peak velocity (effect size 0.84 ±0.66) and mean velocity (0.62 ± 0.88) were meaningful. These findings demonstrate that eliciting an acute STE response in dynamic training movements through contrast training can produce a chronic improvement in dynamic movements as a training effect.

This study investigated the relationship between physical performance and match performance in Australian Rules Football (ARF). Thirty-six semiprofessional ARF players participated in this study. Physical capacity was measured using a 3-km time trial. Match performance was measured throughout the 2013 season through 2 methods: direct game involvements (DGIs) per minute and a recording of coaches' vote after the game. The main finding of the study was that 3-km time trial performance was a significant predictor of DGI per minute (p ≤ 0.05). In addition, the number of senior games played was also significant in predicting DGI per minute (p ≤ 0.05). Furthermore, the number of senior games significantly correlated with coaches' votes (p ≤ 0.05). There were no significant relationships between 3-km time trial and coaches' vote. The results highlight the importance of developing physical capacity in the preseason period; the players who were better performers in the 3-km time trial had a greater number of DGIs per minute. This information is important to consider in preseason planning to ensure sufficient time is dedicated to developing physical capacity in the training program, as it is directly associated with performance. In addition, this research also highlights the importance of playing experience in relation to team selection. Playing experience, as measured by the number of senior games played, had a significant relationship with both measures of match performance.

This study examined the mediating role of drive for muscularity and social physique anxiety (SPA) in the perceived muscular male ideal physique and muscle dysmorphia relationship in weight training men. Men (N = 146, mean ± SD; age, 22.8 ± 5.0 years; weight, 82.0 ± 11.1 kg; height, 1.80 ± 0.07 m; body mass index, 25.1 ± 3.0) who participated in weight training completed validated questionnaires measuring drive for muscularity, SPA, perceived muscular male ideal physique, global muscle dysmorphia, and several characteristics of muscle dysmorphia (exercise dependence, diet manipulation, concerns about size/symmetry, physique protection behavior, and supplementation). Perceived ideal physique was an independent predictor of muscle dysmorphia measures except physique protection (coefficients = 0.113-0.149, p ≤ 0.05). Perceived ideal physique also predicted muscle dysmorphia characteristics (except physique protection and diet) through the indirect drive for muscularity pathway (coefficients = 0.055-0.116, p ≤ 0.05). Perceived ideal physique also predicted size/symmetry concerns and physique protection through the indirect drive for muscularity and SPA pathway (coefficients = 0.080-0.025, p ≤ 0.05). These results extend current research by providing insights into the way correlates of muscle dysmorphia interact to predict the condition. The results also highlight signs (e.g., anxiety about muscularity) that strength and conditioning coaches can use to identify at-risk people who may benefit from being referred for psychological assistance.

The purpose of this article was to compare strength, speed, and power characteristics between playing position (forwards and backs) in elite rugby league players. A total of 39 first team players (height, 183.8 ± 5.95 cm; body mass, 100.3 ± 10.7 kg; age, 24 ± 3 years) from a National Rugby League club participated in this study. Testing included 10-, 40-m sprint times, sprint mechanics on an instrumented nonmotorized treadmill, and concentric isokinetic hip and knee extension and flexion. Backs, observed to have significantly (p ≤ 0.05) lighter body mass (effect size [ES] = 0.98), were significantly faster (10-m ES = 1.26; 40-m ES = 1.61) and produced significantly greater relative horizontal force and power (ES = 0.87 and 1.04) compared with forwards. However, no significant differences were found between forwards and backs during relative isokinetic knee extension, knee flexion, relative isokinetic hip extension, flexion, prowler sprints, sprint velocity, contact time, or flight time. The findings demonstrate that backs have similar relative strength in comparison with forwards, but run faster overground and produce significantly greater relative horizontal force and power when sprinting on a nonmotorized instrumented treadmill. Developing force and power in the horizontal direction may be beneficial for improving sprint performance in professional rugby league players.

A variety of training approaches have been shown to improve running economy in well-trained athletes. However, there is a paucity of data exploring lower-body determinants that may affect running economy and account for differences that may exist between genders. Sixty-three male and female distance runners were assessed in the laboratory for a range of metabolic, biomechanical, and neuromuscular measures potentially related to running economy (ml·kg(-1)·min(-1)) at a range of running speeds. At all common test velocities, women were more economical than men (effect size [ES] = 0.40); however, when compared in terms of relative intensity, men had better running economy (ES = 2.41). Leg stiffness (r = -0.80) and moment arm length (r = 0.90) were large-extremely largely correlated with running economy and each other (r = -0.82). Correlations between running economy and kinetic measures (peak force, peak power, and time to peak force) for both genders were unclear. The relationship in stride rate (r = -0.27 to -0.31) was in the opposite direction to that of stride length (r = 0.32-0.49), and the relationship in contact time (r = -0.21 to -0.54) was opposite of that of flight time (r = 0.06-0.74). Although both leg stiffness and moment arm length are highly related to running economy, it seems that no single lower-body measure can completely explain differences in running economy between individuals or genders. Running economy is therefore likely determined from the sum of influences from multiple lower-body attributes.

Over the past 30 years, endurance volumes have increased by >20% among the rowing elite; therefore, informed decisions about the value of weight training over other possible activities in periodized training plans for rowing need to be made. The purpose of this study was to quantify the changes in lower-body strength development after two 14-week phases of intensive resisted on-water rowing, either incorporating weight training or rowing alone. Ten elite women performed 2 resisted rowing ("towing ropes," e.g., 8 × 3 minutes) plus 6 endurance (e.g., 16-28 km at 70-80% maximum heart rate) and 2 rate-regulated races (e.g., 8,000 m at 24 strokes per minute) on-water each week. After a 4-week washout phase, the 14-week phase was repeated with the addition of 2 weight-training sessions (e.g., 3-4 sets × 6-15 reps). Percent (±SD) and standardized differences in effects (effect size [ES] ± 90% confidence limit) for 5-repetition leg pressing and isometric pulling strength were calculated from data ratio scaled for body mass, log transformed and adjusted for pretest scores. Resisted rowing alone did not increase leg pressing (-1.0 ± 5.3%, p = 0.51) or isometric pulling (5.3 ± 13.4%, p = 0.28) strength. In contrast, after weight training, a moderately greater increase in leg pressing strength was observed (ES = 0.72 ± 0.49, p = 0.03), although differences in isometric pulling strength were unclear (ES = 0.56 ± 1.69, p = 0.52). In conclusion, intensive on-water training including resisted rowing maintained but did not increase lower-body strength. Elite rowers or coaches might consider the incorporation of high-intensity nonfatiguing weight training concurrent to endurance exercise if increases in lower-body strength without changes in body mass are desired.

Knowledge of the relationship between weight room exercises and various rowing performance measures is limited; this information would prove useful for sport-specific assessment of individual needs and exercise prescription. The purpose of this study was to establish strength, power, and muscular endurance exercises for weight room training, which are strong determinants of success in specific performance measures used to assess elite rowers. Nineteen heavyweight elite males determined their repetition maximum (RM) loads for exercises using a Concept 2 DYNO [5, 30, 60 and 120RM leg pressing and seated arm pulling (in Joules)] and free weights [1RM power clean (in kilograms) and 6RM bench pull (in kilograms and watts)]. Rowing performance measures included a 7-stage blood lactate response ergometer test (aerobic condition), time trials (500, 2000, and 5000 m), a peak stroke power test, and a 60-minute distance trial. Pearson correlation moments (r ≥ 0.7) and stepwise multiple linear regression calculations (R ≥ 50%) were used to establish strong common variances between weight room exercises and rowing ergometer performance (p ≤ 0.05). Weight room exercises were strong predictors of 2000-m, 500-m time (in seconds), and peak stroke power performance measures only. Bench pull power (in watts) and 1RM power clean (in kilograms) were the best 2-factor predictors of peak stroke power (R = 73%; standard error of the estimates [SEE] = 59.6 W) and 500 m (R = 70%; SEE = 1.75 seconds); while 5RM leg pressing (in Joules) and either 6RM bench pull (kg) or 60RM seated arm pulling (in Joules) the best predictors of 2000 m (R = 59%; SEE = 6.3 seconds and R = 57%; SEE = 6.4 seconds, respectively). Recommended exercises for weight room training include a 1RM power clean, 6RM bench pull, 5RM leg press, and 60RM seated arm pulling.

The purpose of this research was (a) to examine the performance changes that occur in elite female softball players during 20 weeks of softball training (that included 14 weeks of periodized resistance training [RT]) and (b) to examine the relationship between percent change (%change) in muscle architecture variables and %change in strength, speed, and change of direction performance. Ten female softball players (age = 18.1 ± 1.6 years, height = 166.5 ± 8.9 cm, weight = 72.4 ± 10.8 kg) from a state Australian Institute of Sport softball team were tested for maximal lower-body strength using a 3 repetition maximum for a predicted 1 repetition maximum (1RM) and peak force, peak velocity (PV), and peak power (PP) were measured during jump squats (JS) unloaded and loaded. In addition, the first base (1B) and the second base (2B) sprint performance, change of direction (505) on dominant (D) and nondominant (ND) sides, aerobic capacity, and muscle architecture characteristics of vastus lateralis (VL) including muscle thickness (MT), fascicle length (FL), and pennation angle (θp) were examined. The testing sessions occurred pre, mid, and post training (total 20 week pre- and in-season training period). Changes over time were analyzed by repeated-measures analysis of variance. The relationship between %change in muscle architecture variables and strength, speed, and change of direction variables from pre to post were assessed by Pearson product-moment correlation coefficient. Significant improvements in PV and PP occurred at all JS loads pre- to mid-testing and pre- to post-testing. Significant increases occurred pre-post in absolute 1RM, relative 1RM, 505 ND, and 2B sprint. The strongest relationships were found between %change in VL MT and 1B sprint (r = -0.80, p = 0.06), %change in VL FL and 2B sprint (r = -0.835, p = 0.02), and %change in relative 1RM and 505 D (r = -0.70, p = 0.04). In conclusion, gains in strength, power, and performance can occur during the season in elite softball players who are also engaged in a periodized RT program. Furthermore, changes in performance measures are associated with changes in muscle architecture.

The purpose of this study was to develop a greater understanding of Supercross bicycle motocross (BMX) via notational analysis. Union Cycliste Internationale (UCI) categorized Elite riders (n = 26) were the subjects of the analysis; this event occurred during the UCI BMX World Championships. Video footage was captured and analyzed using Quicktime™ and VideoMotion© software. The movement patterns and time spent pedaling, jumping, and "pumping" were determined for each run. On average, the Elite Men took 39.62 ± 0.78 seconds to complete a track, using 30.45 ± 3.2 pedal strokes and spent 11.83 ± 1.11, 9.64 ± 1.79, and 17.05 ± 1.51 seconds pedaling, jumping, and "pumping," respectively. The Elite Women took 40.95 ± 0.91 seconds to complete a track, using 33.65 ± 5.06 pedal strokes and spent 14.40 ± 2.17, 6.28 ± 1.41, and 17.80 ± 1.83 seconds pedaling, jumping, and "coasting and pumping," respectively. The dominant movement patterns investigated for the start, takeoff, landing, and pumping were hip (∼30 times per lap) and knee extension (~30 per leg per lap) and horizontal shoulder abduction and adduction (20 times per lap). Future research is needed to identify the power and acceleration profiles of the sport, which would be paramount for determining the best practice in testing and preparing BMX athletes. Exercises that specifically target the extensors of the hips, knees, and ankles and the muscles responsible for horizontal shoulder abduction and adduction are recommended.

The purpose of this study was to compare the internal load responses (session rating of perceived exertion [RPE] and salivary cortisol) between simulated and official matches (SM and OM). Ten professional basketball players participated in 2 OMs and 2 SMs during the competition season. Subjects provided saliva samples 30 minutes before the prematch warm-up (PRE) and 10 minutes after the end of the match. Session RPE (CR-10 scale) was assessed 30 minutes after each match. The results from the 2-way analysis of variance showed significant differences for post-OM salivary cortisol as compared with pre-OM values (p < 0.05). No changes were observed for cortisol during the SM. Before the OM, a significant difference in salivary cortisol was observed as compared with pre-SM values (p < 0.05). Moreover, the OM session RPE was significantly greater than that of SM. There was a significant correlation between session RPE and cortisol changes (r = 0.75). In summary, the results of this study showed a greater magnitude of cortisol and session RPE responses after OM as compared with that after SM confirming the hypothesis that a real competition generates a greater stress response than a simulated condition does. The anticipatory effect was also observed in the OM. In addition, the results indicate that session RPE seems to be a viable tool in monitoring internal loads, and the results are useful in providing a better understanding of internal loads imposed by basketball training and competitions. The precise monitoring of these responses might help the coaches to plan appropriate loads maximizing recovery and performance.

The study investigated the effects of circadian rhythm of cortisol (C) and testosterone (T) on maximal force production (Fpeak) and power output (Ppeak). Twenty male university students (mean age = 23.8 ± 3.6 years, height = 177.5 ± 6.4 cm, weight = 78.9 ± 11.2 kg) performed 4 time-of-day testing sessions consisting of countermovement jumps (CMJs), squat jumps (SJ), isometric midthigh pulls (IMTPs), and a 1-repetition maximum (1RM) squat. Saliva samples were collected at 0800, 1200, 1600, and 2000 hours to assess T and C levels on each testing day. Session rate-of-perceived exertion (RPE) scores were collected after each session. The results showed that Fpeak and Ppeak presented a clear circadian rhythm in CMJ and IMTP but not in SJ. One repetition maximum squat did not display a clear circadian rhythm. Session RPE scores collected at 0800 and 2000 hours were significantly (p ≤ 0.05) higher than those obtained at 1200 and 1600 hours. Salivary T and C displayed a clear circadian rhythm with highest values at 0800 hours and lowest at 2000 hours; however, no significant correlation was found between T and C with Fpeak and Ppeak. A very strong correlation was found between Taural with Fpeak of CMJ and IMTP and Ppeak of CMJ (r = 0.86, r = 0.84 and r = 0.8, p ≤ 0.001). The study showed the existence of a circadian rhythm in Fpeak and Ppeak in CMJ and IMTP. The evidence suggests that strength and power training or testing should be scheduled later during the day. The use of Taural seemed to be a more effective indicator of physical performance than hormonal measures, and the use of session RPE should also be closely monitored because it may present a circadian rhythm.

This study tested the hypothesis that the first exercise bout consisting of slow-velocity (30° · s(-1)) maximal lengthening contractions would not affect muscle damage in a subsequent bout consisting of fast-velocity (210° · s(-1)) lengthening contractions. Eighteen men were randomly assigned into either a repeated bout group (n = 10) or control group (n = 8). The repeated bout group performed 2 bouts of exercise consisting of 210 maximal lengthening contractions of the elbow flexors separated by 14 days at a velocity of 30° · s(-1) for the first and 210° · s(-1) for the second bout. The control group performed a single bout of the fast-velocity exercise. Changes in maximal isometric strength, range of motion (ROM), upper-arm circumference, muscle thickness, muscle soreness, serum creatine kinase, and lactate dehydrogenase activities were measured before, immediately after, and 24 to 96 hours after exercise. The repeated bout group showed significantly (p < 0.05) smaller changes in all criterion measures except for muscle soreness after the fast-velocity exercise compared with the control group. A significant (p < 0.05) difference was evident only for ROM between the slow- and fast-velocity bouts of the repeated bout group. These results suggest that slow-velocity exercise reduced muscle damage induced by fast-velocity exercise, although the reduction was not large.

The purpose of this investigation was to examine the relationships between measures of maximal isometric force (peak force [PF]), rate of force development (RFD), vertical jump performance (VJ) and 1-repetition maximum (1RM) strength in recreationally trained men. The subjects in this study were 26 men ([mean +/- SD]: age 22 +/- 1 years; height 175 +/- 7 cm; mass 90 +/- 10 kg). They were tested for PF using the isometric midthigh pull exercise. The 1RM for the squat and bench press exercise were determined as a measure of dynamic strength. Explosive strength was measured as RFD from the isometric force-time curve. Correlations between the variables were calculated using Pearson product moment correlation coefficient. There was a nearly perfect correlation between measures of PF and 1RM squat (r = 0.97, p < 0.05) and 1RM bench press (r = 0.99, p < 0.05). The correlations were very strong between VJ and PF (r = 0.72, p < 0.05) and 1RM bench press (r = 0.70, p < 0.05). There were also strong correlations between VJ and 1RM squat (r = 0.69, p < 0.05). There were no significant correlations with RFD. The results showed that isometric maximum strength determined during the isometric midthigh pull test correlated well with 1RM and VJ testing. However, RFD measured during the same test did not appear to correlate as well with other measures. The isometric midthigh pull provides an efficient method for assessing strength in recreationally trained individuals. Practitioners wishing to obtain performance data related to maximum strength may wish to consider isometric testing as a less time intensive method of testing.

Rubber-based resistance (RBR) bands and standard link steel (SLS) chains are 2 forms of variable resistance used throughout the strength and conditioning and rehabilitation communities. The purpose of this study was to quantify the tension of RBR bands and the mass of SLS chains as a function of displacement (increasing in 10-cm increments). Five sets of RBR bands (14-, 22-, 30-, 48-, and 67-mm widths) and 5 sets of SLS chains (6-, 8-, 10-, 13-, 16-mm diameters) were measured using a load cell and a force plate. The RBR bands exhibited curvilinear tension-deformation relationships and were best represented (R >or= 0.99) by second-order polynomial functions, whereas the SLS chains exhibited linear mass-displacement relationships and were best represented (R = 1) by first-order polynomial functions. There were no significant differences (p > 0.05) in force outputs between the load cell and the force plate testing, although the strain gauge is a relatively cheap and viable method of quantifying the variable resistance of chains and bands. The strength and conditioning practitioner when purchasing bands needs to be aware of resting length differences (3.5-5.2%), which resulted in mean tension imbalances of 8-19% in the same color band. This study provides the strength and conditioning coach and clinician with a methodology to quantify variable resistance, which may be useful in the prescription of specific loading intensities.

The purpose of this study was to investigate (a) the cross-sectional relationship of strength, power, and performance variables in trained female athletes and (b) determine if the relationship between these variables changes over the course of a season. Ten female softball players (age = 18.1 +/- 1.6 years, height = 166.5 +/- 8.9 cm, and weight = 72.4 +/- 10.8 kg) from a state Australian Institute of Sport softball team were tested for maximal lower body strength (one repetition maximum [1RM]), peak force (PF), peak velocity (PV), and peak power (PP) during jump squats unloaded and loaded, unloaded countermovement vertical jump height (VJH) 1 base and 2 base sprint performance and change of direction performance on dominant and nondominant sides. The testing sessions occurred pre, mid, and post a 20-week training period. Relationship between body weight (BW), relative strength (1RM/BW), VJH, relative PP, relative PF, PV, speed, and change of direction variables were assessed by Pearson product-moment correlation coefficient at each testing session. Significant relationships were found across all time points with BW, speed, and change of direction measures (r = 0.70-0.93) and relative strength and measures of speed and change of direction ability (r = -0.73-0.85). There were no significant relationships between VJH and any measure of performance at any time point. In conclusion, BW and relative strength have strong to very strong correlations with speed and change of direction ability, and these correlations remain consistent over the course of the season. However, it seems as if many relationships vary with time, and their relationships should therefore be investigated longitudinally to better determine if these cross-sectional relationships truly reflect a deterministic relationship.

The purpose of this study was to investigate the effect of concurrent resistance and endurance cycle training on physiologic and performance parameters of cyclists. Before and after a 6-week training intervention period, 14 well-trained male cyclists completed a maximal graded exercise test, a 30-km dynamic cycling test with 3 intermittent 250-m and 1-km sprints, and a 1 repetition maximum (1RM) squat test for the assessment of lower-limb strength. Subjects were allocated into 2 groups: a resistance training group (RT; n = 7) that completed a 6-week undulating, periodized resistance training program (3/wk) in conjunction with their regular cycle training and a control group (CON; n = 7) that maintained their usual cycle training. Upon completion of the training intervention, there was no change in graded exercise test parameters in either group, but the RT group showed a significantly greater increase in 1RM squat strength compared with CON (p < 0.05). Moreover, the change in 30-km time trial and sprinting performance did not differ between RT and CON, except for the final 1-km sprint where the percent change in 1-km final sprint performance was greater in CON (+11%) compared with RT (-5%). In conclusion, although concurrent resistance and endurance training in well-trained cyclists enhanced 1RM strength, it did not improve overall cycle time trial performance and in fact was shown to reduce 1-km final cycle sprint performance compared with a CON group performing their normal cycle training.

The Eccentric Utilization Ratio (EUR), which is the ratio of countermovement jump (CMJ) to squat jump (SJ) performance measures, is a useful indicator of training status in elite athletes and their utilization of the stretch-shortening cycle. This investigation sought to determine if EUR was sensitive to different types of resistance training in untrained college-aged males. Twenty-nine college-aged males completed 8 weeks of training and were randomly allocated to 1 of 3 training programs: weight training (n = 10), plyometrics (n = 10), or weightlifting (n = 9). Testing occurred 3 times (pre, mid, post) with a CMJ and SJ conducted on a force plate integrated with a position transducer. Height, weight, and a 1RM (repetition maximum) squat also were measured. Weightlifting significantly (p < 0.05) helped subjects jump higher and produce more power than plyometrics for height and power for both CMJ and SJ results. This investigation indicated EUR did not significantly change, suggesting that this type of performance indicator may not be useful in a recreationally active population. Alternatively, an 8-week training program might not be a long enough time period to see changes in this group of participants. Results did indicate that high-velocity and high-force training programs, consisting of weightlifting and plyometrics, improved lower-body performance, especially in the areas of jump height and power.

The purpose of this investigation was to examine the strength, power, and anthropometric contributors to vertical jump performances that are considered specific to volleyball success, including countermovement vertical jump (CMVJ) and spike jump (SPJ), by examining changes across 12 months in elite volleyball players. Anthropometry (height, mass, summation Sigma 7 skinfolds), vertical jump ability (CMVJ, SPJ, and depth jumps from 35 cm), kinetic and kinematic data from an unloaded and loaded (body mass + 50%) jump squat were assessed before and after 12 months of training in 20 elite male volleyball players. To examine the association between the change in each of the strength, power, and anthropometric variables with the changes in CMVJ and SPJ, a correlation analysis of the percent change of each variable with the percent change in CMVJ and SPJ was performed. A significant correlation (r = 0.47; p = 0.04) was observed between changes in CMVJ and SPJ. Significant (p = 0.006-0.02) improvements in CMVJ were associated with increased peak force in the unloaded (r = 0.61) and loaded jump squat (r = 0.59) and greater relative power and peak velocity in the loaded jump squat (r = 0.49 and 0.51, respectively). The significant increase in CMVJ was strongly associated (r = 0.865; p < 0.001) with an improved depth-jump ability. Significant (p = 0.003-0.03) increases in SPJ were related to increases in relative power (r = 0.64), peak force (r = 0.46), and peak velocity (r = 0.49) in the loaded jump and improved depth-jumping ability (r = 0.591). This study demonstrates that, in an elite population of volleyball players, stretch-shortening cycle performance and the ability to tolerate high stretch loads, as in the depth jump, are critical to improving jumping performance.

The purpose of this study was to investigate the effects of different durations of resistance training on body composition and power in children. The study was a 24-week longitudinal design involving 31 preadolescent children who were overweight or obese (ages 7-12 years), divided into 3 groups and resistance trained 3 times per week. Group 8 (G8) trained for 8 weeks, group 16 (G16) trained for 16 weeks, and group 24 (G24) trained for 24 weeks. All participants were measured at weeks 0, 8, 16, and 24 for body composition and power. Subjects in G8 and G16 continued to be tested during the testing weeks after cessation of their training programs. Body composition and bone mineral content were measured by dual-energy X-ray absorptiometry. Significant improvements in body composition were seen in the initial 8-week training phase, and these improvements were maintained for the subsequent 16 weeks. Significant changes in percent body fat ( approximately 5-7%) were observed at 8 weeks in all 3 groups. Total fat mass decreased significantly at week 8 in G16 and G24 (5.9%). By week 24, total fat mass was significantly reduced by 8.1% in G24. Significant improvements were observed in static jump power, which improved by 10.5% at week 16 in G24. These results suggest that an 8-week resistance training program is sufficient time to significantly change body composition, strength, and power measures in children who are overweight or obese. However, further improvements are realized with longer-duration resistance training programs. On cessation of the training programs, the G8 and G16 groups maintained the benefits of the exercise program until the end of the study period.

Force platforms are used extensively to measure force and power output during countermovement jump (CMJ). The purpose of this study was to examine measurement reliability and validity of commonly used performance measurements derived from ground reaction force (GRF)-time data during CMJ and the influence of sampling at different frequencies. Twenty-four men performed 2 trials of CMJ on a force platform, and GRF-time data were sampled at a rate of 500 Hz. Data obtained at 500 Hz were considered as the reference, and then data were resampled at 400, 250, 200, 100, 50, and 25 Hz, using interpolation. Commonly used power, force, and velocity performance measures were obtained from GRF-time data. Reliability was assessed by intraclass correlation coefficient (ICC) and coefficient of variation (CV) between the 2 trials within the session. Peak power, peak force, and peak velocity were highly reliable across all sampling frequencies (ICC = 0.92-0.98, CV = 1.3-4.1). Percentage differences from 500-Hz reference values ranged from -0.85 to 0.20% at 400 Hz, -1.88 to 0.89% at 250 Hz, -1.80 to 1.31% at 200 Hz, -3.63 to 3.34% at 100 Hz, -11.37 to 6.51% at 50 Hz, and -13.17 to 9.03% at 25 Hz. In conclusion, peak power, force, and velocity measurements derived from GRF to assess leg extensor capabilities are reliable within a test session except for peak rate of force development and time to peak power. With regard to sampling frequency, scientists and practitioners may consider sampling as low as 200 Hz, depending on the purpose of measurement, because the percentage difference is not markedly enlarged until the frequency is 100 Hz or lower.

This research aimed to critically examine the effectiveness of a time-limited and distance-regulated interval training program on subelite field hockey players. Subjects comprised 22 women (26.1 +/- 4.5 years, 62.8 +/- 7.4 kg, 1.7 +/- 0.9 m) and 22 men (22.1 +/- 3.2 years, 74.9 +/- 5.4 kg, 1.8 +/- 0.5 m) field hockey players. Performance tests included a standard 20-m multiple-stage shuttle run (MSSR), a 1000-m repeated-effort (x3) time trial (RTT), and a 100-m repeated-effort (x3) shuttle run (RSR) in an ascending pyramid order. The training program was administered separately to the women and men after a traditional, single-peak, 4-week mesocycle, with the fourth week for recovery. Training consisted of an average total sprint distance of 3000 m per session during a 20-week data collection period, with testing administered pre and post. Initial athlete profiling showed a significant (p < 0.05) gender difference on all performance tests. The MSSR results were 8.6 +/- 2.5 (range 6.7-10.7) and 12.1 +/- 2.4 (10.2-13.5) women and men, respectively. The RTT and RSR times for women and men were 5:34 +/- 0:30 seconds (4:31-6:21), 5:14 +/- 0:30 seconds (4:27-6:02), 4:12 +/- 0:13 seconds (3:50-4:36), and 4:06 +/- 0:13 seconds (3:47-6:02), respectively. After 20 weeks of training, a small to moderate effect size (ES) was calculated for the women's (n = 12) MSSR (ES = 0.74) and RSR (ES = 0.50) results. A distinct improvement in the MSSR resulted after training for men (n = 16), with a moderate ES (1.34). In contrast, completion times in RSR were marginally reduced, with a small ES (0.49). The findings demonstrate that a 3000-m interval-based conditioning program, when conducted in conjunction with normal-skill game play training, can lead to significant improvements in player conditioning during a competitive season. Future research should employ modified performance tests that more accurately reflect the nature of the game.

The purpose of this study was to investigate the effect of an 8-week resistance training program on children who were overweight or obese. Forty-eight children (n = 26 girls and 22 boys; mean age = 9.7 years) participated in an 8-week undulating periodized resistance training program for 3 d x wk-1. Measures of body composition via dual-energy X-ray absorptiometry, anthropometry, strength, and power were made before and after the training intervention. There was a significant decrease in absolute percent body fat of 2.6%(p = 0.003) and a significant increase in lean body mass of 5.3% (p = 0.07). There were no significant changes in height, weight, body mass index, total fat mass, or bone mineral content. There were significant increases in 1-repetition maximum squat (74%), number of push-ups (85%), countermovement jump height (8%), static jump height (4%), and power (16%). These results demonstrate that the resistance training program implemented produces significant changes in body composition and strength and power measures, as well as being well tolerated by the participants. An undulating periodized program provides variation and significantly increases lean body mass, decreases percent body fat, and increases strength and power in children who are overweight and obese.

Measuring and tracking performance variables such as peak power output is essential for assessing the effects of training and for informing adjustments to optimize program design. The purpose of this study was to track the long-term changes in muscular power, velocity, and jump height of elite Australian Rules Football (ARF) players during a 3-year period. Twelve members of an ARF team were tracked during the study. The physical characteristics of the subjects were age, 25.3 6 2.8 years; body mass, 93.0 6 6.8 kg; and height, 192 6 6 cm. The subjects performed unweighted and weighted (40 kg) countermovement jumps (CMJ) and static jumps (SJ). Peak power, jump height, and bar velocity were determined using a force plate and position transducer.Measures of peak power output during both the CMJ and SJ indicated significant (p# 0.001) increases of 13% (effect size [ES] = 0.70) and 17% (ES = 1.77), respectively, during the course of the tracking period. There was also a significant 9% (ES = 0.71) increase in CMJ40 peak power. The subjects' CMJ peak velocity improved by 10.7% (ES = 0.34), and SJ peak velocity improved by 12.6% (ES = 0.37). The data from this study show that elite-level ARF players can continue to increase muscular power and velocity. This information is of interest to strength and conditioning coaches who are interested in improving power performance of their athletes for a long-term period.

This study investigated the effects of ballistic resistance training and strength training on muscle fiber composition, peak force (PF), maximal strength, and peak power (PP). Fourteen males (age = 21.3 +/- 2.9, body mass = 77.8 +/- 10.1 kg) with 3 months of resistance training experience completed the study. Subjects were tested pre and post for their squat one-repetition maximum (1RM) and PP in the jump squat (JS). Peak force and rate of force development (RFD) were tested during an isometric midthigh pull. Muscle biopsies were obtained from the vastus lateralis for analysis of muscle fiber type expression. Subjects were matched for strength and then randomly selected into either training (T) or control (C) groups. Group T performed 8 weeks of JS training using a periodized program with loading between 26 and 48% of 1RM, 3 days per week. Group T showed significant improvement in PP from 4088.9 +/- 520.6 to 5737.6 +/- 651.8 W. Rate of force development improved significantly in group T from 12687.5 +/- 4644.0 to 25343.8 +/- 12614.4 N x s(-1). PV improved significantly from 1.59 +/- 0.41 to 2.11 +/- 0.75 m x s(-1). No changes occurred in PF, 1RM, or muscle fiber type expression for group T. No changes occurred in any variables in group C. The results of this study indicate that using ballistic resistance exercise is an effective method for increasing PP and RFD independently of changes in maximum strength (1RM, PF), and those increases are a result of factors other than changes in muscle fiber type expression.

The purpose of this research project was to evaluate the methodology of an iso-inertial force-velocity assessment utilizing a range of loads and a group of high-performance athletes. A total of 26 subjects (19.8 +/- 2.6 years, 196.3 +/- 9.6 cm, 88.6 +/- 8.9 kg) participated in this study. Interday reliability of various force-time measures obtained during the performance of countermovement jumps with a range of loads was examined, followed by a validity assessment of the various measures' ability to discriminate among performance levels, while the ability of the test protocol to detect training-induced changes was assessed by comparing results before and after an intensive 12-week training period. Force and velocity variables were observed to be reliable (intraclass correlation coefficient 0.74-0.99). Large effect size statistic (ES > 0.50) differences among player groups were observed for peak power (1.36-2.25), relative peak power (1.57-2.42), and peak force (0.74-0.95). Significant (p < 0.05) and large (ES > 0.50) improvements were observed in the kinetic values after the intensive training period. The results of this study indicate that the incremental load power profile is an acceptably reliable, valid, and sensitive method of assessing force and power capabilities of the leg extensors in high-performance and elite volleyball players.

The purpose of this investigation was to examine the potential strength, power, and anthropometric contributors to vertical jump performances that are considered specific to volleyball success: the spike jump (SPJ) and counter-movement vertical jump (CMVJ). To assess the relationship among strength, power, and anthropometric variables with CMVJ and SPJ, a correlation and regression analysis was performed. In addition, a comparison of strength, power, and anthropometric differences between the seven best subjects and the seven worst athletes on the CMVJ test and SPJ test was performed. When expressed as body mass relative measures, moderate correlations (0.53-0.65; p < or = 0.01) were observed between the 1RM measures and both relative CMVJ and relative SPJ. Very strong correlations were observed between relative (absolute height-standing reach height) depth jump performance and relative SPJ (0.85; p < or = 0.01) and relative CMVJ (0.93; p