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Background: Maximal lower-body strength can be assessed both dynamically and isometrically; however, the relationship between the changes in these 2 forms of strength following resistance training is not well understood. Purpose: To systematically review and analyze the effects of resistance training on changes in maximal dynamic (1-repetition-maximum back squat, deadlift, and power clean) and position-matched isometric strength (isometric midthigh pull and the isometric squat). In addition, individual-level data were used to quantify the agreement and relationship between changes in dynamic and isometric strength. Methods: Databases were systematically searched to identify eligible articles, and meta-analysis procedures were performed on the extracted data. The raw results from 4 studies were acquired, enabling bias and absolute reliability measures to be calculated using Bland–Altman test of agreement. Results: Eleven studies met the inclusion criteria, which resulted in 29 isometric–dynamic change comparisons. The overall pooled effect was 0.13 in favor of dynamic testing; however, the prediction interval ranged from g = −0.49 to 0.75. There was no evidence of bias (P =.825) between isometric and dynamic tests; however, the reliability coefficient was estimated to be 16%, and the coefficient of variation (%) was 109.27. Conclusions: As a range of future effects can be expected when comparing isometric to dynamic strength changes following resistance training, and limited proportionality exists between changes in these 2 strength qualities, there is strong evidence that isometric and dynamic strength represent separate neuromuscular domains. These findings can be used to inform strength-assessment models in athlete populations. [ABSTRACT FROM AUTHOR]

Purpose: Ice hockey is a team invasion sport characterized by repeated high-intensity skating efforts, technical and tactical skill, physical contact, and collisions requiring considerable levels of muscular strength. The purpose of this study was to evaluate the relationships between lower-body vertical force–time metrics and skating qualities in subelite female ice hockey players. Methods: A cross-sectional cohort design was employed utilizing 14 athletes (body mass = 66.7 [1.8] kg; height = 171.6 [6.2] cm; age = 21.1 [1.7] y). The relationships between metrics of lower-body strength collected from a drop jump, squat jump, countermovement jump, loaded countermovement jump, and an isometric squat and 4 skating qualities collected from a linear sprint, repeated sprint test, and a multistage aerobic test were evaluated. Results: The regression models revealed a positive relationship between relative peak force in the isometric squat and skating multistage aerobic test performance (r2 =.388; P =.017) and a positive relationship between repeated-sprint ability and eccentric mean force during the loaded countermovement jump (r2 =.595; P =.001). No significant relationships were observed between strength metrics and skating acceleration or maximal velocity. Conclusions: These data suggest that skating ability is most affected by relative isometric strength in female ice hockey players. It is recommended that practitioners focus training on tasks that improve relative force output. It is also recommended that isometric relative peak force be used as a monitoring metric for this cohort. [ABSTRACT FROM AUTHOR]

The term 'priming exercise' has recently been introduced to describe exercise stimuli prescribed to enhance performance within 1–48 hours of that stimulus. Despite evidence of these activities being utilised in competitive settings, the reasoning underpinning the application of priming exercise is not yet clear. Therefore, this study aimed to explore practitioners' perceptions about using priming exercise as a pre-competition strategy to improve performance. Semi-structured interviews were conducted with 28 practitioners involved in prescribing training programs to elite Australian athletes. Reflexive thematic analysis revealed six organising themes (i.e. 'limited and inapplicable research findings', 'consideration of athletes' training age', risk-return of priming session outcomes', 'logistical concerns', 'buy-in' and 'priming exercise prescription') later grouped into a global theme, representing the 'challenges of applying priming exercise'. The findings highlight contextual factors influencing practitioners' use of priming exercise and, based on these considerations, draw attention to the apparent uncertainty about whether these stimuli can be prescribed effectively to improve competition performance in sports. In addition to gaining insight into applied priming strategies, the present findings may be used to inform externally valid and relevant study designs that subsequently guide practice. [ABSTRACT FROM AUTHOR]

Preparing athletes for competition requires the diagnosis and monitoring of relevant physical qualities (e.g., strength, power, speed, endurance characteristics). Decisions regarding test selection that attempt to measure these physical attributes are fundamental to the training process yet are complicated by the myriad of tests and measurements available. This article presents an evidenced based process to inform test measurement selection for the physical preparation of athletes. We describe a method for incorporating multiple layers of validity to link test measurement to competition outcome. This is followed by a framework by which to evaluate the suitability of test measurements based on contemporary validity theory that considers technical, decision-making, and organisational factors. Example applications of the framework are described to demonstrate its utility in different settings. The systems presented here will assist in distilling the range of measurements available into those most likely to have the greatest impact on competition performance. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to map responses over 32 hours following high-load (HL) and moderate-load (ML) half-squat priming. Methods: Fifteen participants completed control, HL (87% 1RM), and ML (65% 1RM) activities in randomized, counterbalanced order. Countermovement jump (CMJ), squat jump (SJ), saliva testosterone, saliva cortisol, and perceptual measures were assessed before and 5 minutes, 8 hours, 24 hours, and 32 hours after each activity. Results are presented as percentage change from baseline and 95% confidence interval (CI). Cliff delta was used to determine threshold for group changes. Results: SJ height increased by 4.5% (CI = 2.2–6.8, Cliff delta = 0.20) 8 hours following HL. CMJ and SJ improved by 6.1% (CI = 2.1–7.8, Cliff delta = 0.27) and 6.5% (CI = 1.2–11.8, Cliff delta = 0.30), respectively, 32 hours after ML. No clear diurnal changes in CMJ or SJ occurred 8 hours following control; however, increases of 3.9% (CI = 2.9–9.2, Cliff delta = 0.26) and 4.5% (CI = 0.9–8.1, Cliff delta = 0.24), respectively, were observed after 32 hours. Although diurnal changes in saliva hormone concentration occurred (Cliff delta = 0.37–0.92), the influence of priming was unclear. Perceived "physical feeling" was greater 8 hours following HL (Cliff delta = 0.36) and 32 hours after ML and control (Cliff delta = 0.17–0.34). Conclusions: HL priming in the morning may result in small improvements in jump output and psychophysiological state in the afternoon. Similar improvements were observed in the afternoon the day after ML priming. [ABSTRACT FROM AUTHOR]

The current study aimed to investigate the acute application of compression socks for recovery after a strenuous bout of lower-body exercise. 58 active young adults (29 females, 29 males) performed ankle range of motion, calf circumference, isometric strength, calf endurance and perceived muscle soreness measures at baseline, and up to 48 hours following a strenuous bout of lower-body exercise. During the 30-minute recovery period, participants were randomly assigned an experimental leg (compression sock - COMP) and a control leg (passive recovery - CON). No significant group x time interactions were recorded (p > .05) and effect sizes were mostly trivial, except for a small decrease in perceived muscle soreness in COMP compared to CON immediately post-recovery (d = -0.29). For both groups, calf circumference increased, and calf endurance was reduced following exercise (p < .001), while perceived muscle soreness increased significantly over the follow-up period compared to baseline (p < .001). The application of compression socks for 30-minutes following intense calf exercise had little effect on physical measures but may result in a small decrease in perceived muscle soreness immediately following their use for recovery. These garments could be a viable recovery option for athletes with a short timeframe in between training bouts. [ABSTRACT FROM AUTHOR]

Purpose: Dozens of variables can be derived from the countermovement jump (CMJ). However, this does not guarantee an increase in useful information because many of the variables are highly correlated. Furthermore, practitioners should seek to find the simplest solution to performance testing and reporting challenges. The purpose of this investigation was to show how to apply dimensionality reduction to CMJ data with a view to offer practitioners solutions to aid applications in high-performance settings. Methods: The data were collected from 3 cohorts using 3 different devices. Dimensionality reduction was undertaken on the extracted variables by way of principal component analysis and maximum likelihood factor analysis. Results: Over 90% of the variance in each CMJ data set could be explained in 3 or 4 principal components. Similarly, 2 to 3 factors could successfully explain the CMJ. Conclusions: The application of dimensional reduction through principal component analysis and factor analysis allowed for the identification of key variables that strongly contributed to distinct aspects of jump performance. Practitioners and scientists can consider the information derived from these procedures in several ways to streamline the transfer of CMJ test information. [ABSTRACT FROM AUTHOR]

Purpose: External counterpulsation (ECP) has previously been used to treat cardiac patients via compression of the lower extremities during diastole to increase venous return and coronary perfusion. However, the effects of ECP on exercise performance and markers of recovery in elite athletes are largely unknown. Methods: On 2 separate occasions, 48 h apart, 7 elite National Rugby League players performed an identical 60-min field-based conditioning session followed by a 30-min period ol either regular ECP treatment or placebo. Power measures during repeated cycle bouts and countermovement jump height and contraction time derivatives were measured at rest and 5 h postexercise. Saliva samples and venous blood samples were taken at rest, postexercise, and 5 h postexercise to assess stress, inflammation, and muscle damage. Results: After ECP treatment, cycling peak power output (P = .028; 11%) and accumulated peak power (P = .027; 14%) increased compared with the placebo condition. Postexercise plasma interleukin 1 receptor antagonist only increased after ECP (P= .024; 84%), and concentiations of plasma interleukin 1 receptor antagonist tended to be higher (P = .093; 76%) 5 h postexercise. Furthermore, testosterone-to-cortisolratio was increased above baseline and placebo 5 h postexercise (P = .017-029; 24-77%). The ratio of postexercise salivary a-amylase to immunoglobulin A decreased after treatment (P = .013; 50%) compared with the placebo contiol. Conclusions. Exercise performance and hormonal indicators of stress were improved and inflammation markers were reduced following acute ECP. [ABSTRACT FROM AUTHOR]

Acceleration is a pivotal quality in Australian football (AF); however, sprint-related hamstring injuries are the most frequent non-contact injury in AF. This case study aimed to determine the effects of an unresisted acceleration biased sprint training program on sprint performance, eccentric hamstring strength, and hamstring muscle architecture. One semi-professional AF athlete undertook 6-weeks of unresisted acceleration training during the off-season period of 2020. Unresisted acceleration training was completed twice weekly, over distances of 5-metres, 10-metres, and 15-metres. A variety of starting positions (2-point, 3-point, walking) were utilised to apply progressive overload. Sprint performance tests of acceleration (0-10m) and maximum speed (30-40m), alongside an eccentric hamstring strength assessment, and a Biceps Femoris Long Head ultrasound were completed before and after the intervention. Fascicle length and hamstring muscle soreness were recorded following each of the 12 training sessions during the intervention. Overall, the athlete improved across all areas of testing, with notable improvements in maximum speed (-7%), mean eccentric strength (+16%), and Biceps Femoris fascicle length (+9%). Furthermore, the reported soreness for the athlete was low, addressing a common barrier for speed and eccentrically biased training. This case study highlights that unresisted sprint training when programmed in line with best practice guidelines is an effective tool to improve sprint performance. The short time frame of adaptation is an encouraging aspect and supports the trainability of these qualities during a typical mesocycle. These findings offer an accessible, effective protocol, that can be modified to address common modifiable risk factors (eccentric hamstring strength and Biceps Femoris Long Head fascicle length) for hamstring strain injury, and simultaneously improve sprint performance. [ABSTRACT FROM AUTHOR]