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BACKGROUND: While linear transducers are the most accurate velocity monitoring devices, the horizontal motion of the barbell seems to affect its measurement error. OBJECTIVE: To explore the effect of cable inclination of the GymAware and T-Force linear transducers on the intra-session reliability and magnitude of kinematic variables during the Smith machine bench press exercise. METHODS: Twenty-eight resistance-trained males performed 2 blocks of 12 repetitions (4 repetitions at 40-60-80%1RM). In half of the repetitions with each load the two measuring systems were either vertically aligned with the barbell or positioned 15-cm away from the vertical projection of the barbell. RESULTS: Displacement and mean velocity variables were recorded with a high and comparable intra-session reliability regardless of the cable position and measuring system (CV=𝑟𝑎𝑛𝑔𝑒 1.79–8.38%; ICC=𝑟𝑎𝑛𝑔𝑒 0.69–0.98). The inclined cable position provided a lower displacement and mean velocity than the vertical cable position and the differences were comparable using both the GymAware (⩽ 1.52 cm; ⩽ 0.05 m⋅s-1) and T-Force (⩽ 1.53 cm; ⩽ 0.04 m⋅s-1). CONCLUSIONS: These results indicate that repeatable findings of kinematic variables can be obtained regardless of the cable position, but for comparative purposes, the cable position should remain constant from the start to the end of the lifts.

Background Velocity loss (VL) experienced in a set during resistance training is often monitored to control training volume and quantify acute fatigue responses. Accordingly, various VL thresholds are used to prescribe resistance training and target different training adaptations. However, there are inconsistencies in the current body of evidence regarding the magnitude of the acute and chronic responses to the amount of VL experienced during resistance training. Objective The aim of this systematic review was to (1) evaluate the acute training volume, neuromuscular, metabolic, and perceptual responses to the amount of VL experienced during resistance training; (2) synthesize the available evidence on the chronic effects of different VL thresholds on training adaptations; and (3) provide an overview of the factors that might differentially influence the magnitude of specific acute and chronic responses to VL during resistance training. Methods This review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Five databases were searched, and studies were included if they were written in English, prescribed resistance training using VL, and evaluated at least one (1) acute training volume, neuromuscular, metabolic, or perceptual response or (2) training adaptation. Risk of bias was assessed using a modified Cochrane Collaboration’s tool for assessing the risk of bias in randomized trials. Multilevel and multivariate meta-regressions were performed where possible. Results Eighteen acute and 19 longitudinal studies met the inclusion criteria, of which only one had more than one risk of bias item assessed as high risk. Based on the included acute studies, it seems that the number of repetitions per set, blood lactate concentration, and rating of perceived exertion generally increase, while countermovement jump height, running sprint times, and velocity against fixed loads generally decrease as VL increases. However, the magnitude of these effects seems to be influenced, among other factors, by the exercise and load used. Regarding training adaptations, VL experienced during resistance training did not influence muscle strength and endurance gains. Increases in VL were associated with increases in hypertrophy (b = 0.006; 95% confidence interval [CI] 0.001, 0.012), but negatively affected countermovement jump (b = − 0.040; 95% CI − 0.079, − 0.001), sprint (b = 0.001; 95% CI 0.001, 0.002), and velocity against submaximal load performance (b = − 0.018; 95% CI − 0.029, − 0.006). Conclusions A graded relationship exists between VL experienced during a set and acute training volume, neuromuscular, metabolic, and perceptual responses to resistance training. However, choice of exercise, load, and individual trainee characteristics (e.g., training history) seem to modulate these relationships. The choice of VL threshold does not seem to affect strength and muscle endurance gains whereas higher VL thresholds are superior for enhancing hypertrophy, and lower VL thresholds are superior for jumping, sprinting, and velocity against submaximal loads performance., CAUL

Weakley, J, Munteanu, G, Cowley, N, Johnston, R, Morrison, M, Gardiner, C, Pérez-Castilla, A, and García-Ramos, A. The criterion validity and between-day reliability of the Perch for measuring barbell velocity during commonly used resistance training exercises. J Strength Cond Res XX(X): 000-000, 2022-This study aimed to assess the criterion validity and between-day reliability (accounting for technological and biological variability) of mean and peak concentric velocity from the Perch measurement system. On 2 testing occasions, 16 subjects completed repetitions at 20, 40, 60, 80, 90, and 100% of 1-repetition maximum in the free-weight barbell back squat and bench press. To assess criterion validity, values from the Perch and a 3-dimensional motion capture system (criterion) were compared. Technological variability was assessed by determining whether the differences between the Perch and criterion for each load were comparable for both testing sessions, whereas between-day reliability with both technological and biological variability was calculated from Perch values across days. Generalized estimating equations were used to calculate R2 and root mean square error, whereas Bland-Altman plots assessed magnitude of difference between measures. To support monitoring of athletes over time, standard error of measurement and minimum detectable changes (MDC) were calculated. There was excellent agreement between the Perch and criterion device, with mean velocity in both exercises demonstrating a mean bias ranging from -0.01 to 0.01 m·s-1. For peak velocity, Perch underestimated velocity compared with the criterion ranging from -0.08 to -0.12 m·s-1 for the back squat and -0.01 to -0.02 m·s-1 for the bench press. Technological variability between-days were all less than the MDC. These findings demonstrate that the Perch provides valid and reliable mean and peak concentric velocity outputs across a range of velocities. Therefore, practitioners can confidently implement this device for the monitoring and prescription of resistance training.

Objective: To explore (1) the goodness of fit of generalized and individualized relationships between the maximum number of repetitions performed to failure (RTF) and the fastest mean velocity and peak velocity of the sets (RTF–velocity relationships), (2) the between-sessions reliability of mean velocity and peak velocity values associated with different RTFs, and (3) whether the errors in the prediction of the RTF under fatigued and nonfatigued conditions differ between generalized and individualized RTF–velocity relationships. Methods: Twenty-three sport-science students performed 4 testing sessions with the prone bench pull exercise in a Smith machine: a 1-repetition-maximum [1RM] session, 2 identical sessions consisting of singles sets of RTF against 4 randomized loads (60%–70%–80%–90%1RM), and 1 session consisting of 4 sets of RTF against the 75%1RM. Results: Individualized RTF–velocity relationships presented a higher goodness of fit (r2 = .96–.97 vs .67–.70) and accuracy (absolute errors = 2.1–2.9 repetitions vs 2.8–4.3 repetitions) in the prediction of the RTF than generalized RTF–velocity relationships. The reliability of the velocity values associated with different RTFs was generally high (average within-subject coefficient of variation = 4.01% for mean velocity and 3.98% for peak velocity). The error in the prediction of the RTF increased by ~1 repetition under fatigue (ie, set 1 vs sets 2–4). Conclusions: Individualized RTF–velocity relationships can be used with acceptable precision and reliability to prescribe the loads associated with a given RTF during the match a specific XRM during the prone bench pull exercise, but a lower accuracy is expected in a fatigued state.

This study aimed to compare the maximal mechanical variables derived from the load-velocity (L-V) relationship and 2000-meter rowing ergometer performance between rowers of different age categories, and to identify the L-V relationship variables more closely related to 2000-meter rowing ergometer performance. Nineteen competitive rowers (15 males and four females) aged between 15 and 25 years were evaluated during the national 2000-meter rowing ergometer competition organised by the Chilean Rowing Federation. Thereafter, the L-V relationship variables (load-axis intercept [

Background: The relationship between the external load lifted and movement velocity can be modeled by a simple linear regression, and the variables derived from the load-velocity (L-V) relationship were recently used to estimate the maximal neuromuscular capacities during 2 variants of the back-squat exercise. Hypothesis: The L-V relationship variables will be highly reliable and will be highly associated with the traditional tests commonly used to evaluate the maximal force and power. Study Design: Twenty-four male wrestlers performed 5 testing sessions (a 1-repetition maximum [1RM] session, and 4 experimental sessions [2 with the concentric-only back-squat and 2 with the eccentric-concentric back-squat]). Each experimental session consisted of performing 3 repetitions against 5 loads (45%-55%-65%-75%-85% of the 1RM), followed by single 1RM attempts. Level of Evidence: Level 3. Methods: Individual L-V relationships were modeled from the mean velocity collected under all loading conditions from which the following 3 variables were calculated: load-axis intercept ( L0), velocity-axis intercept ( v0), and area under the line ( Aline = L0· v0/2). The back-squat 1RM strength and the maximum power determined as the apex of the power-velocity relationship ( Pmax) were also determined as traditional measures of maximal force and power capacities, respectively. Results: The between-session reliability was high for the Aline (coefficient of variation [CV] range = 2.58%-4.37%; intraclass correlation coefficient [ICC] range = 0.98-0.99) and generally acceptable for L0 and v0 (CV range = 5.08%-9.01%; ICC range = 0.45-0.96). Regarding the concurrent validity, the correlations were very large between L0 and the 1RM strength ( rrange = 0.87-0.88) and nearly perfect between Aline and Pmax ( r = 0.98-0.99). Conclusion: The load-velocity relationship variables can be obtained with a high reliability ( L0, v0, and Aline) and validity ( L0 and Aline) during the back-squat exercise. Clinical Relevance: The load-velocity relationship modeling represents a quick and simple procedure to estimate the maximal neuromuscular capacities of lower-body muscles.

BACKGROUND: More practical and less fatiguing strategies have been developed to accurately predict the one-repetition maximum (1RM). OBJETIVE: To compare the accuracy of the estimation of the free-weight bench press 1RM between six velocity-based 1RM prediction methods. METHODS: Sixteen men performed an incremental loading test until 1RM on two separate occasions. The first session served to determine the minimal velocity threshold (MVT). The second session was used to determine the validity of the six 1RM prediction methods based on 2 repetition criteria (fastest or average velocity) and 3 MVTs (general MVT of 0.17 m⋅s-1, individual MVT of the preliminary session, and individual MVT of the validity session). Five loads (≈ 2540557085% of 1RM) were used to assess the individualized load-velocity relationships. RESULTS: The absolute difference between the actual and predicted 1RM were low (range = 2.7–3.7%) and did not reveal a significant main effect for repetition criterion (P= 0.402), MVT (P= 0.173) or their two-way interaction (P= 0.354). Furthermore, all 1RM prediction methods accurately estimated bench press 1RM (P⩾ 0.556; ES ⩽ 0.02; r⩾ 0.99). CONCLUSIONS: The individualized load-velocity relationship provides an accurate prediction of the 1RM during the free-weight bench press exercise, while the repetition criteria and MVT do not appear to meaningfully affect the prediction accuracy.

The aim of this study was to examine the test-retest reliability and concurrent validity of the PUSH Band™ 2.0 to measure barbell’s velocity during unconstrained (free-weights) and constrained (Smith machine) squat exercises. After an initial assessment of the Smith machine squat one-repetition maximum (1RM), 24 resistance-trained males completed one or two testing sessions separated by 7 days. In one session, the squat was performed with free-weights ( n = 22), while in another session, the Smith machine was used ( n = 16). Both testing sessions consisted of two blocks of eight repetitions (three repetitions at 45%1RM, three repetitions at 65%1RM, and two repetitions at 85%1RM). The mean velocity of the lifting phase was simultaneously recorded with the PUSH Band™ 2.0 and a gold-standard linear velocity transducer (T-Force® System). The PUSH Band™ 2.0 generally revealed an acceptable reliability (CVrange = 5.81%–13.14%), but the reliability was always greater for the T-Force® System (CVrange = 2.95%–7.86%). Regardless of the squat exercise, the concurrent validity of the PUSH Band™ 2.0 with respect to the T-Force® System was generally low at 45%1RM (ESrange = 0.18–0.33; rrange = 0.58–0.75; SEErange = 0.04–0.05 ms−1 and 4.2%–6.0%), 65%1RM (ESrange = 0.26–0.44; rrange = 0.63–0.82; SEErange = 0.04–0.06 ms−1 and 6.0%–9.2%), and 85%1RM (ESrange = 0.61–0.64; rrange = 0.66–0.82; SEErange = 0.05–0.07 ms−1 and 11.4%–16.0%). Taken together, these results suggest that the PUSH Band™ 2.0 is a reliable, but not valid, wearable technology to measure the barbell velocity during the free-weight and Smith machine squat exercises.

This study aimed to determine the effect of the intra-session exercise sequence of a concurrent training programme on the components of health-related physical fitness. Twenty-four healthy young adults were allocated into two different groups differing only in the exercise order to conduct an 8-week intra-session concurrent training programme consisting of three sessions of 60-90 minutes (180-270 min/week), with all-out running sprint intervals, back squat, and bench press endurance and resistance exercises (i.e., ET+RT and RT+ET). The 8-week intra-session concurrent training programme overall improved all the components of physical fitness regardless of the exercise sequence. However, ET + RT and RT + ET groups reported moderate and small improvements for squat jump (ET + RT: 3.82 cm [1.11 to 6.53 cm]; RT + ET: 0.31 cm [-1.72 to 2.33 cm]), countermovement jump (ET + RT: 3.76 cm [1.43 to 6.08 cm]; RT + ET: 2.07 cm [-0.03 to 4.17 cm]) and maximum oxygen uptake (ET + RT: 4.75 ml/kg/min [1.14 to 8.35 ml/kg/min]; RT + ET: 1.66 ml/kg/min [-0.89 to 4.21 ml/kg/min]), respectively. Therefore, greater lower-body power and cardiorespiratory fitness gains might be induced following the ET + RT sequence.

We would like to thank all the subjects who selflessly participated in the study. This study was funded by the Spanish Ministry of Science and Innovation (PID2019-110074GB-I00/SRA (State Research Agency)/10.13039/501100011033) and by the grants 451-03-68/2020-14/200015, 451-03-68/2020-14/200021 from the Ministry of education, science, and technological development of Republic of Serbia. The experiments comply with the current laws of the country in which they were performed. The authors have no conflict of interest to declare. The datasets generated during and/or analyzed during the current study are not publicly available, but are available from the corresponding author who was an organizer of the study., This study aimed to compare the between-session reliability of performance and asymmetry variables between unilateral and bilateral standing broad jumps (SBJ). Twenty-four amateur basketball players (12 males and females) completed two identical sessions which consisted of four unilateral SBJs (two with each leg) and two bilateral SBJs. Mean and peak values of force, velocity and power, and impulse were obtained separately for each leg using a dual force platform. Inter-limb asymmetries were computed using the standard percentage difference for the unilateral SBJ, and the bilateral asymmetry index-1 for the bilateral SBJ. All performance variables generally presented an acceptable absolute reliability for both SBJs (CV range = 3.65-9.81%) with some exceptions for mean force, mean power, and peak power obtained with both legs (CV range = 10.00-15.46%). Three out of 14 variables were obtained with higher reliability during the unilateral SBJ (CVratio >= 1.18), and 5 out of 14 during the bilateral SBJ (CVratio >= 1.27). Asymmetry variables always showed unacceptable reliability (ICCrange = -0.40 to 0.58), and slight to fair levels of agreement in their direction (Kappa range = -0.12 to 0.40) except for unilateral SBJ peak velocity [Kappa = 0.52] and bilateral SBJ peak power [Kappa = 0.51]) that showed moderate agreement for both SBJs. These results highlight that single-leg performance variables can be generally obtained with acceptable reliability regardless of the SBJ variant, but the reliability of the inter-limb asymmetries in the conditions examined in the present study is unacceptable to track individual changes in performance., Spanish Government PID2019-110074GB-I00/SRA, Ministry of education, science, and technological development of Republic of Serbia 451-03-68/2020-14/200015 451-03-68/2020-14/200021

Low-intensity aerobic exercise is recommended to reduce intraocular pressure (IOP) levels. However, this effect depends on several factors. We found that using an elevation training mask (ETM) during low-intensity aerobic exercise causes an IOP rise.The aim was to assess the influence of wearing an ETM on IOP during low-intensity endurance training.Sixteen physically active young adults (age=23.9±2.9 y) cycled during 30 minutes at 10% of maximal power production with and without an ETM in 2 different days and randomized order. A rebound tonometer was used to measure IOP at baseline, after a warm-up of 5 minutes, during cycling (6, 12, 18, 24, and 30 min), and recovery (5 and 10 min) by rebound tonometry.The use of an ETM significantly affects the IOP behaviour during exercise (P0.001, ηp²=0.66). In the ETM condition, there was an IOP increment during exercise (P0.001, ηp²=0.28) whereas an IOP-lowering effect was observed in the control condition (P0.001, ηp²=0.41). Post hoc comparisons showed that there were greater IOP values during exercise in the ETM condition in comparison to the control condition (average IOP difference=3.7±2.2 mm Hg; corrected P0.01, and the Cohen d's1.10, in all cases).Low-intensity endurance exercise causes an increment in IOP when it is performed wearing an ETM and a decrease in IOP when the air flow is not restricted (control condition). Therefore, the ETM should be discouraged during low-intensity endurance exercise for individuals who need to reduce IOP levels (eg, glaucoma patients or those at risk). However, the external validity of these results needs to be addressed in future studies with the inclusion of glaucoma patients.

An a-posteriori multicentre reliability study was conducted to compare the reliability and magnitude of the maximum power (Pmax) and optimal velocity (Vopt) between the force-power-velocity relatio...

This study explored the influence of different take-off thresholds on the reliability and magnitude of countermovement jump (CMJ) performance variables. Twenty-three men were tested on two separate...

Background: The possibility to selectively assess the force exerted by each leg during bilateral jumps has allowed sport scientists to explore inter-leg asymmetries, this metric being a rich source of research due to its potential applications to improve sports performance and reduce the risk of injury. The purpose of this study was to explore the reliability and agreement of single-leg mechanical performance and inter-leg asymmetry variables obtained by two procedures of analysis (Synchronous [simultaneous jump detection for both legs] and Asynchronous [specific jump detection for each leg]) during bilateral countermovement jumps (CMJs). Method: During a single testing session, 74 participants performed 5 maximal height bilateral CMJs on dual force platforms (Kistler, model 9260AA6, Winterthur, Switzerland), and the 2 trials that differed the least in terms of squat depth and jump height were considered for statistical analyses. The following mechanical variables were calculated separately for each leg using the Synchronous and Asynchronous procedures: mean force, peak force, and propulsive impulse. Results: The procedures showed comparable reliability, except for mean force and propulsive impulse of the left leg (higher for the Asynchronous procedure). The agreement between the procedures was very high, while the most reliable mechanical variable was mean force (CV≈2.9%, ICC≈0.98), followed by peak force (CV≈4.4%, ICC≈0.96) and propulsive impulse (CV≈6.4%, ICC≈0.91). Reliability of inter-leg asymmetries was greater using mean and peak force (ICC range=0.74–0.82) than using propulsive impulse (ICC range = 0.65–0.66). Significance: Both Synchronous and Asynchronous procedures can be used to evaluate single-leg mechanical performance (mean force, peak force, and propulsive impulse) and asymmetries, whereas mean force should be used to evaluate single-leg mechanical performance and mean or peak force to assess asymmetries., Ministry of Education, Science & Technological Development, Serbia 451-03-68/2020-14/200015 451-03-68/2020-14/200021, Universidad de Granada/CBUA

Background: The aim of the present study was to explore whether military-specific reaction time (RT) test performance is affected by individuals’ physical and visual skills. Method: In a single testing session, the military-specific Simple and Go, No-Go RT, aerobic power (20-m Multistage Shuttle Run test), maximal upper- and lower-body mechanical capacities (bench press and squat against different loads), and visual skills (multiple object tracking and dynamic visual acuity) of 30 young men (15 active-duty military personnel and 15 sport science students) were evaluated. Results: The main findings revealed that the Simple RT and Go, No-Go RT presented (1) with aerobic power non-significant small correlations in military personnel (r = −0.39 and −0.35, respectively) and non-significant negligible correlations in sport science students (r = −0.10 and 0.06, respectively), (2) inconsistent and generally non-significant correlations with the maximal mechanical capacities of the upper- and lower-body muscles (r range = −0.10, 0.67 and −0.27, 0.48, respectively), (3) non-significant correlations with visual skills (r magnitude ≥ 0.58) with the only exception of the Go, No-Go RT that was significantly correlated to all visual variables in the group of students (i.e., students who achieved better results during visual tests had shorter RT; r magnitude ≥ 0.58), and (4) none of the physical and visual variables significantly predicted the Simple RT or Go, No-Go RT. Conclusion: Altogether, these results indicate that military-specific RT performance is generally independent of physical and visual skills in both military personnel and active university students., CEMIX (Centro Mixto UGR-MADOC, Army of Spain) 5/4/20 TR-COMBATE, Ministry of Education, Science & Technological Development, Serbia 451-03-9/2021-14/200154

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Perez-Castilla, A, Boullosa, D, and Garcia-Ramos, A. Reliability and validity of the iLOAD application for monitoring the mean set velocity during the back squat and bench press exercises performed against different loads. J Strength Cond Res 35(2S): S57-S65, 2021-This study aimed to evaluate the reliability and validity of a smartphone application (iLOAD) for the monitoring of mean concentric velocity (MV) during resistance training sets. Twenty males completed 2 identical sessions consisting of one set of 10 repetitions against 4 loads (25, 40, 55, 70% of the one repetition maximum [1RM]) during the back squat and bench press exercises. The MV of the 5 initial repetitions and for the whole set were determined simultaneously with the iLOAD application and a linear velocity transducer (LVT). Two independent researchers operated the iLOAD application during the experimental sessions to evaluate the interrater agreement for the assessment of MV. An acceptable but generally lower reliability was observed for iLOAD (coefficient of variation [CV] range: 5.61-9.79%) compared to the LVT (CV range: 4.51-8.18%) at 25-40-55% of 1RM, whereas the reliability at 75% of 1RM was acceptable for the LVT during the bench press (CV range: 6.37-8.26%), but it was unacceptable for the iLOAD during both exercises (CV range: 11.3-12.8%) and for the LVT during the back squat (CV range: 11.3-17.4%). Small to moderate differences (ES range: 0.24-1.04) and very high to practically perfect correlations (r range: 0.70-0.90) were observed between the iLOAD and the LVT. A very high agreement was observed between both raters for the recording of MV during the back squat and bench press exercises (r ≥ 0.98). Taken together, these results suggest that the iLOAD application can be confidently used to quantify the MV of training sets during the squat and bench press exercises not performed to failure.

Purpose: To compare the load–velocity (L-V) relationship between bench-press exercises performed using 4 different grip widths, to determine the association between the anthropometric characteristics and L-V profile, and to explore whether a multiple linear-regression model with movement velocity and subjects’ anthropometric characteristics as predictor variables could increase the goodness of fit of the individualized L-V relationship. Methods: The individual L-V relationship of 20 men was evaluated by means of an incremental loading test during the bench-press exercise performed on a Smith machine using narrow, medium, wide, and self-selected grip widths. Simple and multiple linear-regression models were performed. Results: The mean velocity associated with each relative load did not differ among the 4 grip widths (P ≥ .130). Only body height and total arm length were correlated with the mean velocity associated with light and medium loads (r ≥ .464). A slightly higher variance of the velocity attained at each relative load was explained when some anthropometric characteristics were used as predictor variables along with the movement velocity (r2 = .969 [.965–.973]) in comparison with the movement velocity alone (r2 = .966 [.955–.968]). However, the amount of variance explained by the individual L-V relationships was always higher than with the multiple linear-regression models (r2 = .995 [.985–1.000]). Conclusions: These results indicate that the individual determination of the L-V relationship using a self-selected grip width could be recommended to monitor relative loads in the Smith machine bench-press exercise.

Pestaña-Melero, FL, Jaric, S, Pérez-Castilla, A, Rojas, FJ, and García-Ramos A. Comparison of mechanical outputs between the traditional and ballistic bench press: role of the type of variable. J Strength Cond Res 34(8): 2227-2234, 2020-This study aimed to comprehensively explore the differences in mechanical outputs between the bench press (BP) and the bench press throw (BPT) exercises performed by 21 men (age: 22.0 ± 4.2 years, body mass: 73.4 ± 7.7 kg, height: 177.2 ± 8.0 cm, and concentric-only [C-O] BP 1 repetition maximum: 81.3 ± 6.8 kg) against a fixed external load of 27 kg using both the (C-O) and eccentric-concentric (E-C) execution techniques. The types of variables collected by means of a linear velocity transducer were the traditional mean values (i.e., from the first positive velocity until the barbell reaches maximum height), mean propulsive values (i.e., from the first positive velocity until the barbell acceleration become lower than gravity), mean values of the acceleration phase (i.e., from the first positive velocity until the barbell acceleration become negative), and maximum values (i.e., the highest instantaneous value of the concentric phase) of force, velocity, and power. The magnitude of the effect sizes (the negative sign indicates a higher value for the BP as compared to the BPT) ranged from -0.10 to -2.19 for force, 0.28 to 1.30 for velocity, and -0.73 to 0.67 for power variables, remaining mainly similar for the (C-O) and (E-C) execution techniques. These results highlight that the comparison of force, velocity, and power outputs between the BP and BPT exercises is largely affected by the type of variable considered. The shortcomings of linear position transducers in accurately determining the end point of the concentric phase suggest that the maximum values, particularly the maximum velocity, should be reported to assess ballistic performance.

García-Pinillos, F, Lago-Fuentes, C, Bujalance-Moreno, P, and Pérez-Castilla, A. Effect of the menstrual cycle when estimating 1 repetition maximum from the load-velocity relationship during the bench press exercise. J Strength Cond Res 36(3): e55-e58, 2022-This study aimed to examine the effect of the ovulatory menstrual cycle (MC) when estimating the 1 repetition maximum (1RM) from the individual load-velocity relationship during the bench press (BP) exercise. Nine resistance-trained eumenorrheic women (age: 28.7 ± 3.6 years) were tested in 3 different phases across the MC: menstrual or early follicular phase (i.e., testing between days 1-3), follicular or late follicular phase (i.e., testing between days 7-10), and luteal or mid-luteal phase (i.e., testing between days 19-21). Each testing trial consisted of an incremental loading protocol against 4 loading conditions (≈50-70-80-90% 1RM) in the concentric-only BP exercise. A smartphone application (MyLift) was used to collect the mean velocity (MV) of all repetitions. The 1RM was estimated from the individual load-velocity relationship by applying a linear regression model as the load associated with an MV of 0.17 m·s-1. In addition, the MV obtained at each %1RM (i.e., from 20% 1RM to 80% 1RM in 20% increments), the load-velocity slope (i.e., the decrease in MV per each 1% of increment in the %1RM), and the y-intercept (i.e., the estimate of MV at 0% 1RM) were computed from the individual load-velocity relationships. No significant differences were observed between the 3 phases of the MC for any of the measured load-velocity relationship parameters (corrected p-value ≥0.495; effect size ≤0.24). The results suggest that the estimation of the BP 1RM from the load-velocity relationship seems not to vary over the 3 different phases of the MC (i.e., menstrual, follicular, and luteal phases).

This study aimed to determine whether the provision of jump height feedback (knowledge of result; KR) can increase the performance and the consistency of output variables. In a randomised order, sixteen participants performed six squat or countermovement jumps (three from a 90o knee angle and three from a self-preferred knee angle) with or without KR over four sessions. The provision of KR significantly increased peak force (p = 0.046, 1.83%), mean force (p = 0.037, 1.45%), peak velocity (p < 0.001, 3.71%), mean velocity (p = 0.004, 3.44%), peak power (p < 0.001, 4.22%) and mean power (p = 0.001, 4.69%). A high within-session reliability was observed for all variables (coefficient of variation [CV] ≤ 5.62%, intraclass correlation coefficient [ICC] ≥ 0.95). No systematic differences in reliability were detected between the jumps performed without KR (CV = 3.00 ± 1.38%, ICC = 0.97 ± 0.03) and with KR (CV = 3.04 ± 1.49%, ICC = 0.97 ± 0.04). These results suggest that the provision of jump height feedback during vertical jump testing is effective to enhance vertical jump performance but it does not reduce the variability between jumps.

Pérez-Castilla, A, García-Ramos, A, Padial, P, Morales-Artacho, AJ, and Feriche, B. Load-velocity relationship in variations of the half-squat exercise: influence of execution technique. J Strength Cond Res 34(4): 1024-1031, 2020-Previous studies have revealed that the velocity of the bar can be used to determine the intensity of different resistance training exercises. However, the load-velocity relationship seems to be exercise dependent. This study aimed to compare the load-velocity relationship obtained from 2 variations of the half-squat exercise (traditional vs. ballistic) using 2 execution techniques (eccentric-concentric vs. concentric-only). Twenty men performed a submaximal progressive loading test in 4 half-squat exercises: eccentric-concentric traditional-squat, concentric-only traditional-squat, countermovement jump (i.e., ballistic squat using the eccentric-concentric technique), and squat jump (i.e., ballistic squat using the concentric-only technique). Individual linear regressions were used to estimate the 1 repetition maximum (1RM) for each half-squat exercise. Thereafter, another linear regression was applied to establish the relationship between the relative load (%RM) and mean propulsive velocity (MPV). For all exercises, a strong relationship was observed between %RM and MPV: eccentric-concentric traditional-squat (R = 0.949), concentric-only traditional-squat (R = 0.920), countermovement jump (R = 0.957), and squat jump (R = 0.879). The velocities associated with each %RM were higher for the ballistic variation and the eccentric-concentric technique than for the traditional variation and concentric-only technique, respectively. Differences in velocity among the half-squat exercises decreased with the increment in the relative load. These results demonstrate that the MPV can be used to predict exercise intensity in the 4 half-squat exercises. However, independent regressions are required for each half-squat exercise because the load-velocity relationship proved to be task specific.

This study examined the differences in the bench press one-repetition maximum obtained by three different methods (direct method, lifts-to-failure method, and two-point method). Twenty young men were tested in four different sessions. A single grip width (close, medium, wide, or self-selected) was randomly used on each session. Each session consisted of an incremental loading test until reaching the one-repetition maximum, followed by a single set of lifts-to-failure against the 75% one-repetition maximum load. The last load lifted during the incremental loading test was considered the actual one-repetition maximum (direct method). The one-repetition maximum was also predicted using the Mayhew’s equation (lifts-to-failure method) and the individual load–velocity relationship modeled from two data points (two-point method). The actual one-repetition maximum was underestimated by the lifts-to-failure method (range: 1–2 kg) and overestimated by the two-point method (range: –3 to –1 kg), being these differences accentuated using closer grip widths. All predicted one-repetition maximums were practically perfectly correlated with the actual one-repetition maximum ( r ≥ 0.95; standard error of the estimate ≤ 4 kg). The one-repetition maximum was higher using the medium grip width (83 ± 3 kg) compared to the close (80 ± 3 kg) and wide (79 ± 3 kg) grip widths ( P ≤ 0.025), while no significant differences were observed between the medium and self-selected (81 ± 3 kg) grip widths ( P = 1.000). In conclusion, although both the Mayhew’s equation and the two-point method are able to predict the actual one-repetition maximum with an acceptable precision, the differences between the actual and predicted one-repetition maximums seem to increase when using close grip widths.

A military-specific reaction time (RT) test was developed to explore its reliability and sensitivity to discriminate between military personnel and sport science students. Fifteen male professional Spanish soldiers and 16 male sport science students completed two RT test modalities: military-specific and nonspecific RT tests. For each RT test modality, both the Simple (i.e., one stimulus, one response) and the Go, No-Go RT (i.e., true, and false stimuli, one response) were tested. The military-specific RT test consisted of a video presented through virtual reality glasses of a forest environment in which soldiers would appear from behind different bushes (stimuli) and the response consisted of pressing the button of a gun-shaped mouse (when they saw a soldier pointing a rifle at them). Both Simple and Go, No-Go RT reached acceptable reliability in both populations (coefficient of variation ≤ 9.64%). Military personnel presented a lower RT than sport science students during the military-specific RT test (p ≤ .001), while no differences were obtained during the nonspecific RT test. RT values were not significantly correlated between the military-specific and nonspecific RT tests (r ≤ .02). These findings collectively suggest that the novel military-specific RT test is an ecologically valid alternative to evaluate the information processing abilities of military personnel.

Purpose This study aimed to examine the reliability and validity of load−velocity relationship variables obtained through the two-point method using different load combinations and velocity variables. Methods Twenty men performed 2 identical sessions consisting of 2 countermovement jumps against 4 external loads (20 kg, 40 kg, 60 kg, and 80 kg) and a heavy squat against a load linked to a mean velocity of 0.55 m/s (load0.55). The load−velocity relationship variables (load-axis intercept (L0), velocity-axis intercept (v0), and area under the load−velocity relationship line (Aline)) were obtained using 3 velocity variables (mean velocity (MV), mean propulsive velocity (MPV), and peak velocity (PV)) by the multiple-point method including (20-40-60-80-load0.55) and excluding (20-40-60-80) the heavy squat, as well as from their respective two-point methods (20-load0.55 and 20-80). Results The load−velocity relationship variables were obtained with an acceptable reliability (coefficient of variation (CV) ≤ 7.30%; intra-class correlation coefficient ≥ 0.63). The reliability of L0 and v0 was comparable for both methods (CVratio (caculated as higher value/lower value) = 1.11–1.12), but the multiple-point method provided Aline with a greater reliability (CVratio = 1.26). The use of a heavy squat provided the load-velocity relationship variables with a comparable or higher reliability than the use of a heavy countermovement jump load (CVratio = 1.06–1.19). The PV provided the load-velocity relationship variables with the greatest reliability (CVratio = 1.15–1.86) followed by the MV (CVratio = 1.07–1.18), and finally the MPV. The two-point methods only revealed an acceptable validity for the MV and MPV (effect size ≤ 0.19; Pearson's product-moment correlation coefficient ≥ 0.96; Lin's concordance correlation coefficient ≥ 0.94). Conclusion The two-point method obtained from a heavy squat load and MV or MPV is a quick, safe, and reliable procedure to evaluate the lower-body maximal neuromuscular capacities through the load−velocity relationship.

Ocular physiology is sensitive to cognitively demanding tasks. However, it is unknown whether the intraocular pressure is also affected by the cognitive demands of military operations. The main objective was to determine the impact of a virtual reality shooting simulation with two levels of complexity on intraocular pressure levels in military personnel. Eighteen active-duty members of the Spanish Army and eighteen civilians performed two 4 min simulated shooting tasks with two levels of complexity using a virtual reality. In the “easy” task participants performed a simulated shoot when the stimulus (military with a rifle) appeared, while in the “difficult” task the stimulus randomly was a military with a rifle or with his hands on the air and participants were instructed to respond only when the military with a rifle appeared. Intraocular pressure was measured with a rebound tonometer before and immediately after each task. Complementarily, perceived levels of mental load and shooting performance (reaction time) were assessed. Intraocular pressure was greater after completing the more complex task in both military personnel (p-value < 0.01, Cohen´s d = 1.19) and civilians (p-value < 0.01, Cohen´s d = 1.16). Also, perceived levels of task load and reaction time were higher in the difficult compared to the easy shooting tasks (both p < 0.001). The rise in intraocular pressure is positively associated with the cognitive demands of simulated military operations. The potential application of this finding is the development of objective tools based on intraocular pressure for the evaluation of the mental state in real-world contexts, permitting to improve soldiers´safety and performance., CEMIX (Centro Mixto UGR-MADOC, Army of Spain) 5/4/20 TR-COMBATE

This study aimed to explore the relationship between the inter-limb differences in unilateral countermovement (CMJ) height and the inter-limb differences in bilateral CMJ force production, and to elucidate whether the self-reported preferred leg contributes more to force production than the non-preferred leg. Twenty-three senior basketball players performed in a single session eight unilateral CMJs (four with each leg) and four bilateral CMJs. Impulse, peak force, mean force were recorded during the bilateral CMJ, and jump height during the unilateral CMJ.

Objective: To compare the accuracy of different devices to predict the bench-press 1-repetition maximum (1RM) from the individual load–velocity relationship modeled through the multiple- and 2-point methods. Methods: Eleven men performed an incremental test on a Smith machine against 5 loads (45–55–65–75–85%1RM), followed by 1RM attempts. The mean velocity was simultaneously measured by 1 linear velocity transducer (T-Force), 2 linear position transducers (Chronojump and Speed4Lift), 1 camera-based optoelectronic system (Velowin), 2 inertial measurement units (PUSH Band and Beast Sensor), and 1 smartphone application (My Lift). The velocity recorded at the 5 loads (45–55–65–75–85%1RM), or only at the 2 most distant loads (45–85%1RM), was considered for the multiple- and 2-point methods, respectively. Results: An acceptable and comparable accuracy in the estimation of the 1RM was observed for the T-Force, Chronojump, Speed4Lift, Velowin, and My Lift when using both the multiple- and 2-point methods (effect size ≤ 0.40; Pearson correlation coefficient [r] ≥ .94; standard error of the estimate [SEE] ≤ 4.46 kg), whereas the accuracy of the PUSH (effect size = 0.70–0.83; r = .93–.94; SEE = 4.45–4.80 kg), and especially the Beast Sensor (effect size = 0.36–0.84; r = .50–.68; SEE = 9.44–11.2 kg), was lower. Conclusions: These results highlight that the accuracy of 1RM prediction methods based on movement velocity is device dependent, with the inertial measurement units providing the least accurate estimate of the 1RM.

This study aimed to explore the effect of the velocity and depth of the countermovement on vertical jump performance and the shape of the force-time curve. Seventeen university students performed two blocks of 18 countermovement jumps (CMJ) being instructed to jump for maximum height after performing the countermovement at a self-selected (SS-CMJ) or fast (F-CMJ) velocity. Each block consisted of six CMJ from a larger depth, six CMJ from a shorter depth, and six CMJ from a self-preferred depth. Mean and peak values of force, velocity and power, reactive strength index-modified (RSImod), jump height, and the shape of the force-time curve (unimodal or bimodal) were assessed. The F-CMJ provided a higher (mean and peak force, mean velocity, mean power, and RSImod) or comparable (peak power, peak velocity, and jump height) performance than the SS-CMJ. The shorter CMJ provided the highest values of mean and peak force, mean and peak power, and RSImod, while peak velocity and jump height were higher for the larger and self-preferred CMJ. The force-time curve was bimodal during the larger CMJ (100%) and unimodal during the shorter CMJ (65-88%). These results highlight that CMJ performance is influenced by the velocity and depth of the countermovement.

There is a growing interest in the analysis of different methods for monitor fatigue during resistance training sessions. This study aimed to (1) analyse the relationships between the percentage of performed repetitions with respect to the maximum possible number (%REP), RPE and magnitude of velocity loss (VL), and (2) examine whether a multiple regression analysis with the RPE and VL as predictor variables could improve the goodness of fit to predict %REP in the bench press exercise performed in a Smith machine. Seven men performed a repetition maximum test, on 3 separate testing sessions, against 3 different absolute loads based on a target mean velocity (MV) according to an individual load-velocity profile (≈1.00, ≈0.70, and ≈0.50 m/s). MV, VL, %REP and RPE were collected and used for analysis. Based upon quadratic polynomial regression analysis strong relationships were reported between the RPE and %REP (