The Use of Free Weight Squats in Sports: A Narrative Review-Squatting Movements, Adaptation, and Sports Performance: Physiological.

ABSTRACT: Stone, MH, Hornsby, G, Mizuguchi, S, Sato, K, Gahreman, D, Duca, M, Carroll, K, Ramsey, MW, Stone, ME, and Haff, GG. The use of free weight squats in sports: a narrative review-squatting movements, adaptation, and sports performance: physiological. J Strength Cond Res 38(8): 1494-1508, 2024-The squat and its variants can provide numerous benefits including positively affecting sports performance and injury prevention, injury severity reduction, and rehabilitation. The positive benefits of squat are likely the result of training-induced neural alterations and mechanical and morphological adaptations in tendons, skeletal muscles, and bones, resulting in increased tissue stiffness and cross-sectional area (CSA). Although direct evidence is lacking, structural adaptations can also be expected to occur in ligaments. These adaptations are thought to beneficially increase force transmission and mechanical resistance (e.g., resistance to mechanical strain) and reduce the likelihood and severity of injuries. Adaptations such as these, also likely play an important role in rehabilitation, particularly for injuries that require restricted use or immobilization of body parts and thus lead to a consequential reduction in the CSA and alterations in the mechanical properties of tendons, skeletal muscles, and ligaments. Both volume and particularly intensity (e.g., levels of loading used) of training seem to be important for the mechanical and morphological adaptations for at least skeletal muscles, tendons, and bones. Therefore, the training intensity and volume used for the squat and its variations should progressively become greater while adhering to the concept of periodization and recognized training principles.

Two Days Versus Four Days of Training Cessation Following a Step-Taper in Powerlifters.

ABSTRACT: Burke, BI, Carroll, KM, Travis, SK, Stone, ME, and Stone, MH. Two days versus four days of training cessation following a step-taper in powerlifters. J Strength Cond Res 37(12): e625-e632, 2023-Tapering and training cessation are methods of training load management aimed at optimizing athlete preparedness leading into competition. Such practices are often used by strength sport athletes such as powerlifters (i.e., athletes who compete in the back squat [BS], bench press [BP], and deadlift [DL]). The purpose of this study was to compare the differences in maximal strength, subjective recovery and stress state, and body composition alterations in strength athletes undergoing a 1-week step-taper followed by either a 2-day (2D) or 4-day (4D) period of training cessation. Twelve powerlifters (22.3 ± 2.1 yrs; 92.1 ± 20.4 kg; 174.8 ± 7.5 cm) completed a 6-week training protocol aimed at peaking 1 repetition maximum (1RM) strength on BS, BP, and DL. Body composition, subjective recovery and stress state, and 1RM on BS, BP, and DL were assessed before an overreach week (T1) and after the periods of training cessation (T2) for each group. Alpha criterion was set at p ≤ 0.05. There were significant increases in BP ( p = 0.032, g = 0.10), powerlifting total ( p = 0.014, g = 0.11), and DOTS score ( p = 0.006, g = 0.12) after 2D of cessation. However, after 4D of cessation, significant increases were only observed in DL ( p = 0.019, g = 0.11) along with significant decreases in BP ( p = 0.003, g = -0.13). There were no statistically significant changes in any other variable for either group indicating that BS, psychometric, and body composition data were maintained between T1 and T2. The results of this study support the use of 1-week step-tapers, followed by a short period of training cessation (2-4D) to maintain or improve maximal strength performance.

Alterations in Adiponectin, Leptin, Resistin, Testosterone, and Cortisol across Eleven Weeks of Training among Division One Collegiate Throwers: A Preliminary Study.

Cytokine and hormone concentrations can be linked to the manipulation of training variables and to subsequent alterations in performance. SUBJECTS: Nine D-1 collegiate throwers and 4 control subjects participated in this preliminary and exploratory report. METHODS: Hormone (testosterone (T) and cortisol (C)) and adipokine (adiponectin, leptin, and resistin) measurements were taken at weeks 1, 7, and 11 for the throwers and weeks 1 and 11 for the control group. The throwers participated in an 11-week periodized resistance training and throws program during the fall preparatory period. Volume load was recorded throughout the study. RESULTS: Hormone values did not exhibit statistically significant changes across time; however, there were notable changes for C, the testosterone to cortisol ratio (T:C), and adiponectin. CONCLUSIONS: T:C was increased as volume load decreased, and adiponectin increased in concert with decreases in C and increases in the T:C, possibly suggesting a lesser degree of obesity-related inflammation and a higher degree of "fitness" and preparedness.

Strength gains: block versus daily undulating periodization weight training among track and field athletes.

Recently, the comparison of "periodized" strength training methods has been a focus of both exercise and sport science. Daily undulating periodization (DUP), using daily alterations in repetitions, has been developed and touted as a superior method of training, while block forms of programming for periodization have been questioned. Therefore, the purpose of this study is to compare block to DUP in Division I track and field athletes. Thirty-one athletes were assigned to either a 10-wk block or DUP training group in which sex, year, and event were matched. Over the course of the study, there were 4 testing sessions, which were used to evaluate a variety of strength characteristics. Although performance trends favored the block group for strength and rate of force development, no statistically significant differences were found between the 2 training groups. However, statistically different (P ≤ .05) values were found for estimated volume of work (volume load) and the amount of improvement per volume load between block and DUP groups. Based on calculated training efficiency scores, these data indicate that a block training model is more efficient than a DUP model in producing strength gains.

Relationship between strength characteristics and unweighted and weighted vertical jump height.

PURPOSE: To investigate the relationship between maximum strength and differences in jump height during weighted and unweighted (body weight) static (SJ) and countermovement jumps (CMJ). METHODS: Sixty-three collegiate athletes (mean +/- SD; age= 19.9 +/- 1.3 y; body mass = 72.9 +/- 19.6 kg; height = 172.8 +/- 7.7 cm) performed two trials of the SJ and CMJ with 0 kg and 20 kg on a force plate; and two trials of mid-thigh isometric clean pulls in a custom rack over a force plate (1000-Hz sampling). Jump height (JH) was calculated from flight time. Force-time curve analyses determined the following: isometric peak force (IPF), isometric force (IF) at 50, 90, and 250 ms, and isometric rates of force development (IRFD). Absolute and allometric scaled forces, [absolute force/(body mass(0.67))], were used in correlations. RESULTS: IPF, IRFD, F50(a), F50, F90, and F250 showed moderate/strong correlations with SJ and CMJ height percent decrease from 0 to 20 kg. IPF(a) and F250(a) showed weak/moderate correlations with percent height decrease. Comparing strongest (n = 6) to weakest (n = 6): t tests revealed that stronger athletes (IPF(a)) performed superior to weaker athletes. CONCLUSION: Data indicate the ability to produce higher peak and instantaneous forces and IRFD is related to JH and to smaller differences between weighted and unweighted jump heights. Stronger athletes jump higher and show smaller decrements in JH with load. A weighted jump may be a practical method of assessing relative strength levels.

Effect of warm-up on the standing broad jump in trained and untrained men and women.

The effect of 3 warm-up routines on standing broad jump (SBJ) performance was investigated. Thirty-two men and women participated as subjects. Following the determination of 1-repetition maximum (1RM) squat, subjects completed warm-up routines and broad jumps on 4 occasions in a randomized order. Subjects performed SBJ immediately (POST) and 15 min following (POST15) the given warm-up routine. The routines were high force, consisting of high % 1RM, low repetition squats; high power, consisting of low % 1RM, low repetition speed squats; stretching, consisting of static stretches; and no activity, a control condition. Repeated measures analysis of covariance (ANCOVA) revealed no differences among broad jump performance following any of the warm-up routines (p = 0.157). A strong correlation (R = 0.805) was found between 1RM squat and SBJ. These data indicate that warm-up of any type has little effect on jump performance and that maximum strength is strongly related to jumping ability.

Maximum strength-power-performance relationships in collegiate throwers.

Presently the degree to which peak force influences power production or explosive performance such as strength training movements or throwing (shot-put and weight-throw) is unclear. This study describes the relationships between a measure of maximum strength, isometric peak force (IPF), dynamic peak force (PF), peak power (PP), the 1-repetition movement power snatch (SN), and throwing ability over an 8-week training period. Five male and 6 female (n = 11) well-trained collegiate throwers participated. PF was measured using an AMTI force plate; PP was measured using an infrared-ultrasonic tracking device (V-Scope, Lipman Electronics). Clean pulls from the midthigh position were assessed isometrically and dynamically at a constant load, 30% and 60% of IPF. Specific explosive strength was evaluated using an SN and using the shot-put (SP) and weight-throw (WGT) measured under meet conditions. Variables (PF, PP, SN) were assessed 3 times at 0 weeks, 4 weeks, and 8 weeks. Each measurement period preceded a field meet by 3 days. Peak force, peak rate of force development, and PP increased over the 8 weeks. Correlation coefficients (r) indicate that IPF is strongly related to dynamic PF and PP 30%, 60% of the IPF. Furthermore, strong correlations were found for the SN and the distance for the SP and WGT, and these relationships tended to increase over time. Results suggest that maximum strength (i.e., IPF) is strongly associated with dynamic PF. In addition, maximum strength is strongly associated with PP even at relatively light loads such as those associated with sport-specific dynamic explosiveness (i.e., SN, SP, WGT).