Standardized vs. Relative Intensity in CrossFit

CrossFit is characterized by being a standardized training program that improves physical performance through the provision of several stimuli regardless of the participant's strength level. This study aimed to compare the acute response in total repetitions as a measurement of performance, jump ability, physiological demand (heart rate and blood lactate), and perceived effort considering the participants' strength level with individualized intensity in CrossFit. Thirty-five participants were assessed and asked to participate on two separate days in a standardized and relative 'As Many Repetitions As Possible' (AMRAP) CrossFit circuit. Both AMRAPs comprised strength, gymnastic and aerobic exercises, although only strength was individualized according to the participant's level. Before the statistical analysis, participants were allocated to higher- or lower-strength groups following the one-repetition maximum-bodyweight ratio in the push press exercise. Results support the existence of a strong relationship between strength level and total repetitions in both AMRAPs. In addition, differences in total repetitions and rate of perceived exertion between strength groups are discarded when AMRAP intensity is individualized while physiological demand and jump ability are maintained. Thus, the higher-strength participants may benefit from similar responses with a lower number of repetitions. Therefore, CrossFit trainers should be encouraged to prescribe strength tasks based on the percentage of 1RM for every training.

The effect of rest redistribution on kinetic and kinematic variables during the hang pull

The aim of this study was to compare the effects of rest redistribution (RR) on kinetics and kinematics during the hang pull (HP). Twenty-one male athletes (age 29.5 ± 4.3 years, height 1.78 ± 0.07 m, body mass 75.17 ± 11.11 kg, relative one repetition maximum [1RM] power clean [PC] 1.17 ± 0.14 kg.kg-1) performed the HP using 140% of 1RM PC with 3 traditional sets of 6 repetitions (TS), 9 sets of 2 repetitions with RR [45s rest after 2 repetitions] (RR45) and 6 sets of 3 repetitions with RR [72s rest after 3 repetitions] (RR72). Peak velocity (PV) was higher during RR72 (1.18 ± 0.11 m.s-1) compared to RR45 (1.14 ± 0.11 m.s-1) for the average of 18 repetitions (p = 0.025, g = 0.36). There was a main effect for set configuration with greater peak force (PF) (p < 0.001, g = 0.14) during RR72 compared to RR45, with greater PV and impulse (p < 0.001, g = 0.19-0.36) during RR72 compared to RR45. There was also greater peak velocity maintenance (PVM) (p = 0.042, g = 0.44) for RR72 compared to RR45. There were no significant or meaningful differences (p > 0.05, g = 0.00-0.59) between configurations for any other variables. Rest redistribution protocols did not result in significantly or meaningfully greater kinetics or kinematics during the HP when compared to a TS protocol; although performing RR72 resulted in higher PF, PV, and impulse, with improved PVM compared to RR45.

The Relationship Between Isometric and Dynamic Strength Following Resistance Training: A Systematic Review, Meta-Analysis, and Level of Agreement

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.

Construction of a physical fitness evaluation index system and model for high-level freestyle skiing aerials athletes in China

OBJECTIVE

This study aims to enhance the competitive level of Chinese freestyle skiing aerials athletes by developing a specialized physical fitness evaluation index system and model tailored for high-level Chinese athletes. This system intends to provide theoretical references and training monitoring schemes in preparation for the 25th Milan Winter Olympics.

METHODS

A study was conducted on 29 high-level Chinese freestyle skiing aerials athletes. Physical fitness test indexes were selected using a literature review, expert interviews, and questionnaire surveys, and athletes were tested. Athletes were ensured to be in optimal physical condition before testing. Based on the test results, the representative indexes of the evaluation system are finally determined by combining R-type clustering analysis, multiple linear regression analysis. Determine index weights through weight questionnaires and normalization, and develop evaluation standards through methods such as percentile counting and weighted scoring.

RESULTS

Physical fitness evaluation system for Chinese freestyle skiing aerialists includes three aspects: evaluation index, index weight, and evaluation standard. The evaluation indexes include 3 first-level, 11 second-level, and 11 third-level indexes of body form, physiological function, and physical quality. In the evaluation weight, physical quality is ranked first, and physiological function and body form rank second and third, respectively. The evaluation standard consists of a scoring evaluation standard and a rating evaluation standard. Based on the index system, this study constructs the general and ideal physical fitness model of China's high-level freestyle aerials athletes.

CONCLUSION

The constructed physical fitness evaluation system effectively represents physical fitness development status of high-level freestyle skiing aerials athletes, providing a basis for creating personalized training plans. The established model serves as a reference for athletes' physical fitness development objectives.

Effects of high-intensity functional training on physical fitness and sport-specific performance among the athletes: A systematic review with meta-analysis

OBJECTIVE

This study aims to meta-analyze the impact of high-intensity functional training on athletes' physical fitness and sport-specific performance.

METHODS

A systematic search was conducted in five well-known academic databases (PubMed, Scopus, Web of Science, EBSCOhost, and the Cochrane Library) up to July 1, 2023. The literature screening criteria included: (1) studies involving healthy athletes, (2) a HIFT program, (3) an assessment of outcomes related to athletes' physical fitness or sport-specific performance, and (4) the inclusion of randomized controlled trials. The Physical Therapy Evidence Database (PEDro) scale was used to evaluate the quality of studies included in the meta-analysis.

RESULTS

13 medium- and high-quality studies met the inclusion criteria for the systematic review, involving 478 athletes aged between 10 and 24.5 years. The training showed a small to large effect size (ES = 0.414-3.351; all p < 0.05) in improving upper and lower body muscle strength, power, flexibility, and sport-specific performance.

CONCLUSION

High-intensity functional training effectively improves athletes' muscle strength, power, flexibility, and sport-specific performance but has no significant impact on endurance and agility. Future research is needed to explore the impact of high-intensity functional training on athletes' speed, balance, and technical and tactical performance parameters.

Maturity Offset, Anthropometric Characteristics and Vertical Force-Velocity Profile in Youth Basketball Players

This work aimed to analyze the relationships between maturity offset, anthropometric variables and the vertical force-velocity profile in youth (12-18 years old) male basketball players. The vertical force-velocity profile was measured in 49 basketball players, grouped in competitive-age categories, i.e., under 14, 16 and 18 years of age (U-14, U-16 and U-18, respectively). A bivariate correlational analysis was carried out between maturity offset, anthropometric variables (height, body mass, % fat, muscle mass, bone mass and body mass index (BMI)) and vertical force-velocity profile (theoretical maximal force [F0], theoretical maximal velocity [V0], theoretical maximal power [Pmax], force-velocity imbalance [Fvimb] and force-velocity profile orientation). The results showed significant correlations (p < 0.05) between Fvimb and maturity offset at early ages of training (12-15 years). The anthropometric profile was correlated (p < 0.05) with F0 in U-14, V0 in U-16, and Pmax in U-18 basketball players. The current findings suggest a relationship between the vertical force-velocity imbalance and maturity offset and the main vertical force-velocity profile variables. The vertical force-velocity profile is hypothesized as a useful index to correct vertical force-velocity deficits according to the maturity offset of male basketball players.

Molecular investigation of the effect of weightlifting training on helper T cell subsets in female weightlifting athletes: an immune profiling panel

BACKGROUND

In this study, it was aimed to molecularly investigate the changes in the helper T (Th) cell subgroups of intense weightlifting training. For this purpose, transcription factor and cytokine expressions of Th1, Th2, Th17, and regulator T cell (Treg) cells were evaluated.

METHODS

Eight elite weightlifting athletes were included in the study. Within the scope of the study, transcription factor and cytokine expressions of Th cell subgroups were evaluated by real-time polymerase chain reaction (qPCR) method before training, after intense training with 90-100% capacity, and after 120 minutes of rest from training.

RESULTS

As a result of the study, when the pre-training and post-training expressions were compared, an increase in Th1 and Th2 cell factors and a decrease in Th17 and Treg cell-related expressions were detected. These changes were statistically significant (P<0.05). The changes in expressions after training and after 120 minutes of rest were not statistically significant (P>0.05).

CONCLUSIONS

Changes have been detected in Th cell subgroups due to intense weightlifting training, and these changes are the first study conducted with female weightlifters.

Intentionally Slow Concentric Velocity Resistance Exercise and Strength Adaptations: A Meta-Analysis

ABSTRACT

Hermes, MJ and Fry, AC. Intentionally slow concentric velocity resistance exercise and strength adaptations: a meta-analysis. J Strength Cond Res 37(8): e470-e484, 2023-Intentionally slow-velocity resistance exercise (ISVRE) is suggested by some to be equally or more effective than fast or traditional velocities for increasing muscular strength. The purpose of this meta-analysis was to assess the effect ISVRE has on strength adaptations compared with faster or traditional velocities, with subgroup analyses exploring age, sex, and training status as confounding factors on the influence of velocity on strength adaptation. Eligible studies (n = 24) were required to be chronic (multiple weeks) randomized or nonrandomized comparative studies using dynamic constant external resistance for training and testing, and pre-post strength assessments. All studies examined healthy individuals (n = 625; fast or traditional n = 306, intentionally slow n = 319). A random-effects meta-analysis indicated a significant (p ≤ 0.05) effect in favor of fast training (effect size [ES] = 0.21, 95% confidence interval [CI] = 0.02-0.41, p = 0.03). Publication bias was noted through trim and fill analysis, with an adjusted effect size estimate of 0.32 (p < 0.001). Subgroup analyses indicated no difference between trained and untrained subjects (QM = 0.01, p = 0.93), and no difference between older and younger subgroups (QM = 0.09, p = 0.77), despite younger favoring faster (ES = 0.23, p = 0.049) and older not favoring either velocity (ES = 0.16, p = 0.46). Subgroup analysis also indicated women favored faster training (ES = 0.95, p < 0.001) in comparison to men (ES = 0.08, p = 0.58). Contrary to some previous reviews, these results indicate that chronic fast or traditional velocity resistance exercise increases muscular strength to a greater degree than ISVRE training. Resistance training velocity must be considered if strength is a desired outcome.

Association Between Foundation Strength and Weightlifting Exercises in Highly Trained Weightlifters: Support for a General Strength Component

ABSTRACT

Zecchin, A, Puggina, EF, Hortobágyi, T, and Granacher, U. Association between foundation strength and weightlifting exercises in highly trained weightlifters: support for a general strength component. J Strength Cond Res 37(7): 1375-1381, 2023-In addition to specific weightlifting exercises (i.e., clean and jerk and snatch), foundation strength exercises (i.e., overhead press, front squat, and deadlift) constitute an integral part of the weightlifters' training regime. The unexamined concept behind this training plan is that foundation strength exercises are associated with clean and jerk and snatch performance, implying the existence of a general strength component. We thus determined the relationship between performance in foundation strength exercises (overhead press, front squat, and deadlift) and weightlifting exercises (clean and jerk and snatch) in weightlifters. Well-trained weightlifters ( N = 19, age: 26.8 ± 4.4 years; body mass index: 27.6 ± 2.3 kg·m -2 ; and training history: 4.6 ± 0.8 years) performed 1 repetition maximum tests (1RM) in foundation strength and weightlifting exercises, over 14 days, in a randomized order. We observed significant correlations in 1RM performance between the overhead press and snatch ( r = 0.69), front squat and snatch ( r = 0.73), overhead press and clean and jerk ( r = 0.67), and front squat and clean and jerk ( r = 0.72, all r values: p < 0.01). No significant correlations were found for 1RM performance between the snatch and deadlift or between the clean and jerk and deadlift ( r- range: 0.20-0.58; p > 0.05). Stepwise linear regression revealed that 1RM performance in the overhead press and front squat explained 62% of the variance in snatch 1RM performance ( F = 5.51; p < 0.04). Overhead press and front squat 1RM performance explained 59% of the variance in the clean and jerk 1RM performance ( F = 5.14; p < 0.04). Our results demonstrate the existence of a general strength component between selected foundation strength exercises and weightlifting performance. However, the use of the front squat and overhead press to increase 1RM performance in weightlifting exercises needs to be determined in future research using a different methodological approach (i.e., longitudinal protocols), given that the observed correlations do not necessarily imply causation.

National Strength and Conditioning Association Position Statement on Weightlifting for Sports Performance

ABSTRACT

Comfort, P, Haff, GG, Suchomel, TJ, Soriano, MA, Pierce, KC, Hornsby, WG, Haff, EE, Sommerfield, LM, Chavda, S, Morris, SJ, Fry, AC, and Stone, MH. National Strength and Conditioning Association position statement on weightlifting for sports performance. J Strength Cond Res XX(X): 000-000, 2022-The origins of weightlifting and feats of strength span back to ancient Egypt, China, and Greece, with the introduction of weightlifting into the Olympic Games in 1896. However, it was not until the 1950s that training based on weightlifting was adopted by strength coaches working with team sports and athletics, with weightlifting research in peer-reviewed journals becoming prominent since the 1970s. Over the past few decades, researchers have focused on the use of weightlifting-based training to enhance performance in nonweightlifters because of the biomechanical similarities (e.g., rapid forceful extension of the hips, knees, and ankles) associated with the second pull phase of the clean and snatch, the drive/thrust phase of the jerk and athletic tasks such as jumping and sprinting. The highest force, rate of force development, and power outputs have been reported during such movements, highlighting the potential for such tasks to enhance these key physical qualities in athletes. In addition, the ability to manipulate barbell load across the extensive range of weightlifting exercises and their derivatives permits the strength and conditioning coach the opportunity to emphasize the development of strength-speed and speed-strength, as required for the individual athlete. As such, the results of numerous longitudinal studies and subsequent meta-analyses demonstrate the inclusion of weightlifting exercises into strength and conditioning programs results in greater improvements in force-production characteristics and performance in athletic tasks than general resistance training or plyometric training alone. However, it is essential that such exercises are appropriately programmed adopting a sequential approach across training blocks (including exercise variation, loads, and volumes) to ensure the desired adaptations, whereas strength and conditioning coaches emphasize appropriate technique and skill development of athletes performing such exercises.

Reliability, Validity, and Comparison of Barbell Velocity Measurement Devices during the Jump Shrug and Hang High Pull

This study examined the reliability, potential bias, and practical differences between the GymAware Powertool (GA), Tendo Power Analyzer (TENDO), and Push Band 2.0 (PUSH) during the jump shrug (JS) and hang high pull (HHP) performed across a spectrum of loads. Fifteen resistance-trained men performed JS and HHP repetitions with 20, 40, 60, 80, and 100% of their 1RM hang power clean, and mean (MBV) and peak barbell velocity (PBV) were determined by each velocity measurement device. Least-products regression and Bland-Altman plots were used to examine instances of proportional, fixed, and systematic bias between the TENDO and PUSH compared to the GA. Hedge's g effect sizes were also calculated to determine any meaningful differences between devices. The GA and TENDO displayed excellent reliability and acceptable variability during the JS and HHP while the PUSH showed instances of poor-moderate reliability and unacceptable variability at various loads. While the TENDO and PUSH showed instances of various bias, the TENDO device demonstrated greater validity when compared to the GA. Trivial-small differences were shown between the GA and TENDO during the JS and HHP exercises while trivial-moderate differences existed between GA and PUSH during the JS. However, despite trivial-small effects between the GA and PUSH devices at 20 and 40% 1RM during the HHP, practically meaningful differences existed at 60, 80, and 100%, indicating that the PUSH velocity outputs were not accurate. The TENDO appears to be more reliable and valid than the PUSH when measuring MBV and PBV during the JS and HHP.

Propulsion Phase Characteristics of Loaded Jump Variations in Resistance-Trained Women

The purpose of this study was to compare the propulsion phase characteristics of the jump squat (JS), hexagonal barbell jump (HEXJ), and jump shrug (JShrug) performed across a spectrum of relative loads. Thirteen resistance-trained women (18-23 years old) performed JS, HEXJ, and JShrug repetitions at body mass (BM) or with 20, 40, 60, 80, or 100% BM during three separate testing sessions. Propulsion mean force (MF), duration (Dur), peak power output (PP), force at PP (F_PP), and velocity at PP (V_PP) were compared between exercises and loads using a series of 3 × 6 repeated measures ANOVA and Hedge's g effect sizes. There were no significant differences in MF or Dur between exercises. While load-averaged HEXJ and JShrug PP were significantly greater than the JS, there were no significant differences between exercises at any individual load. The JShrug produced significantly greater F_PP than the JS and HEXJ at loads ranging from BM-60% BM, but not at 80 or 100% BM. Load-averaged V_PP produced during the JS and HEXJ was significantly greater than the JShrug; however, there were no significant differences between exercises at any individual load. Practically meaningful differences between exercises indicated that the JShrug produced greater magnitudes of force during shorter durations compared to the JS and HEXJ at light loads (BM-40%). The JS and HEXJ may be classified as more velocity-dominant exercises while the JShrug may be more force-dominant. Thus, it is important to consider the context in which each exercise is prescribed for resistance-trained women to provide an effective training stimulus.

Field-Based Biomechanical Assessment of the Snatch in Olympic Weightlifting Using Wearable In-Shoe Sensors and Videos-A Preliminary Report

Traditionally, the biomechanical analysis of Olympic weightlifting movements required laboratory equipment such as force platforms and transducers, but such methods are difficult to implement in practice. This study developed a field-based method using wearable technology and videos for the biomechanical assessment of weightlifters. To demonstrate the practicality of our method, we collected kinetic and kinematic data on six Singapore National Olympic Weightlifters. The participants performed snatches at 80% to 90% of their competition one-repetition maximum, and the three best attempts were used for the analysis. They wore a pair of in-shoe force sensors loadsol^® (novel, Munich, Germany) to measure the vertical ground reaction forces under each foot. Concurrently, a video camera recorded the barbell movement from the side. The kinematics (e.g., trajectories and velocities) of the barbell were extracted using a free video analysis software (Kinovea). The power-time history was calculated from the force and velocity data. The results showed differences in power, force, and barbell velocity with moderate to almost perfect reliability. Technical inconsistency in the barbell trajectories were also identified. In conclusion, this study presented a simple and practical approach to evaluating weightlifters using in-shoe wearable sensors and videos. Such information can be useful for monitoring progress, identifying errors, and guiding training plans for weightlifters.

Comparison between Olympic Weightlifting Lifts and Derivatives for External Load and Fatigue Monitoring

Load management is an extremely important subject in fatigue control and adaptation processes in almost all sports. In Olympic Weightlifting (OW), two of the load variables are intensity and volume. However, it is not known if all exercises produce fatigue of the same magnitude. Thus, this study aimed to compare the fatigue prompted by the Clean and Jerk and the Snatch and their derivative exercises among male and female participants, respectively. We resorted to an experimental quantitative design in which fatigue was induced in adult individuals with weightlifting experience of at least two years through the execution of a set of 10 of the most used lifts and derivatives in OW (Snatch, Snatch Pull, Muscle Snatch, Power Snatch, and Back Squat; Clean and Jerk, Power Clean, Clean, High Hang Clean, and Hang Power Clean). Intensity and volume between exercises were equalized (four sets of three repetitions), after which one Snatch Pull test was performed where changes in velocity, range of motion, and mean power were assessed as fatigue measures. Nine women and twelve men participated in the study (age, 29.67 ± 5.74 years and 28.17 ± 5.06 years, respectively). The main results showed higher peak velocity values for the Snatch Pull test when compared with Power Snatch (p = 0.008; ES = 0.638), Snatch (p < 0.001; ES = 0.998), Snatch Pull (p < 0.001, ES = 0.906), and Back Squat (p < 0.001; ES = 0.906) while the differences between the Snatch Pull test and the derivatives of Clean and Jerk were almost nonexistent. It is concluded that there were differences in the induction of fatigue between most of the exercises analyzed and, therefore, coaches and athletes could improve the planning of training sessions by accounting for the fatigue induced by each lift.

Muscle Architectural and Force-Velocity Curve Adaptations following 10 Weeks of Training with Weightlifting Catching and Pulling Derivatives

The aims of this study were to examine the muscle architectural, rapid force production, and force-velocity curve adaptations following 10 weeks of resistance training with either submaximal weightlifting catching (CATCH) or pulling (PULL) derivatives or pulling derivatives with phase-specific loading (OL). 27 resistance-trained men were randomly assigned to the CATCH, PULL, or OL groups and completed pre- and post-intervention ultrasound, countermovement jump (CMJ), and isometric mid-thigh pull (IMTP). Vastus lateralis and biceps femoris muscle thickness, pennation angle, and fascicle length, CMJ force at peak power, velocity at peak power, and peak power, and IMTP peak force and force at 100-, 150-, 200-, and 250 ms were assessed. There were no significant or meaningful differences in muscle architecture measures for any group (p > 0.05). The PULL group displayed small-moderate (g = 0.25-0.81) improvements in all CMJ variables while the CATCH group displayed trivial effects (g = 0.00-0.21). In addition, the OL group displayed trivial and small effects for CMJ force (g = -0.12-0.04) and velocity variables (g = 0.32-0.46), respectively. The OL group displayed moderate (g = 0.48-0.73) improvements in all IMTP variables while to PULL group displayed small-moderate (g = 0.47-0.55) improvements. The CATCH group displayed trivial-small (g = -0.39-0.15) decreases in IMTP performance. The PULL and OL groups displayed visible shifts in their force-velocity curves; however, these changes were not significant (p > 0.05). Performing weightlifting pulling derivatives with either submaximal or phase-specific loading may enhance rapid and peak force production characteristics. Strength and conditioning practitioners should load pulling derivatives based on the goals of each specific phase, but also allow their athletes ample exposure to achieve each goal.

Predicting the Clean Movement Technique in Crossfit® Athletes Using an Optimal Upper-Limb Range of Motion: A Prospective Cohort Study

BACKGROUND

The aim of this study was to determine the optimal upper-limb range of motion (ROM) profile for the catch phase of the clean movement (CPCM) and to identify the key ROMs for performing the CPCM in CrossFit^® athletes.

METHODS

A prospective cohort study of twenty CrossFit^® athletes aged 20-36 years was conducted. Data were collected regarding age, anthropometrics, CrossFit^® training experience and upper-limb ROM. The ROM was measured using the ROM-SPORT method. After 7 months, athletes performed a clean movement with a load of 80% one repetition maximum. A Bayesian Student's t-analysis, binary logistic regression analysis and Receiver Operating Characteristic analysis were performed.

RESULTS

The optimal upper-limb ROM profile that predicted correct CPCM performance was 78° in shoulder extension, 173° in shoulder flexion, 107° in shoulder external rotation, 89° in shoulder internal rotation, 153° in elbow flexion, 99° in elbow pronation and 92° in wrist extension (area under the curve ≥ 651; positive predictive value ≥ 80%). Shoulder external rotation, elbow pronation and wrist extension were found to be the most important ROMs for the efficient and safe performance of CPCM (area under the curve ≥ 854; positive predictive value ≥ 85.7%).

CONCLUSION

The upper-limb ROM profile is associated with proper clean performance. Further studies are warranted to determine whether improving flexibility on upper-limb ROM may improve proper clean movement performance.

Weightlifting derivatives vs. plyometric exercises: Effects on unloaded and loaded vertical jumps and sprint performance

The aim of this study was to compare the effects of weightlifting derivatives (WL) and plyometric exercises (PLYO) on unloaded and loaded vertical jumps and sprint performance. Initially, 45 resistance-trained men underwent a 4-week WL learning period. Then, the participants were randomly assigned to 1 of 3 groups (WL (n = 15), PLYO (n = 15), and control group (CG) (n = 15)) and followed a training period of 8 weeks. The WL group performed exercises to stimulate the entire force-velocity profile, while the PLYO group performed exercises with an emphasis in vertical- and horizontal-oriented. The CG did not perform any exercise. Pre- and post-training assessments included peak power output (PPO) and jump height (JH) in the squat jump (SJ), countermovement jump (CMJ), CMJ with 60% and 80% of the body mass (CMJ60% and CMJ80%, respectively), and mean sprinting speeds over 5, 10, 20, and 30 m distances. From pre- to post-training, PLYO significantly increased (p≤0.05) PPO and JH in the SJ, PPO during CMJ, and PPO and JH in the CMJ60%; however, no significant changes were observed in JH during CMJ, and PPO and JH in the CMJ80%. For WL and CG, no significant changes were observed in the unloaded and loaded vertical jumps variables. PLYO also resulted in significant improvements (p≤0.05) for 5, 10, and 20 m sprint speeds, but not for 30 m. For WL and CG, no significant changes were observed for all sprint speeds. In conclusion, these data demonstrate that PLYO was more effective than a technically-oriented WL program to improve unloaded and loaded vertical jumps and sprint performance.

Comparing biomechanical time series data across countermovement shrug loads

The effect of load on time-series data has yet to be investigated during weightlifting derivatives. This study compared the effect of load on the force-time and velocity-time curves during the countermovement shrug (CMS). Twenty-nine males performed the CMS at relative loads of 40%, 60%, 80%, 100%, 120%, and 140% one repetition maximum (1RM) power clean (PC). A force plate measured the vertical ground reaction force (VGRF), which was used to calculate the barbell-lifter system velocity. Time-series data were normalized to 100% of the movement duration and assessed via statistical parametric mapping (SPM). SPM analysis showed greater negative velocity at heavier loads early in the unweighting phase (12-38% of the movement), and greater positive velocity at lower loads during the last 16% of the movement. Relative loads of 40% 1RM PC maximised propulsion velocity, whilst 140% 1RM maximized force. At higher loads, the braking and propulsive phases commence at an earlier percentage of the time-normalized movement, and the total absolute durations increase with load. It may be more appropriate to prescribe the CMS during a maximal strength mesocycle given the ability to use supramaximal loads. Future research should assess training at different loads on the effects of performance.

Within Session Exercise Sequencing During Programming for Complex Training: Historical Perspectives, Terminology, and Training Considerations

The primary aim of this narrative review was to outline the historical genesis of resistance training strategies that incorporate high-load, low-velocity exercises and low-load, high-velocity exercises in the same training session allowing for different "exercise sequences" to be simultaneously implemented. Discrepancies between scientific works and the terminology used within contemporary sport science publications are identified. Upon review of the literature, we propose "complex training" to be considered an umbrella term with 4 different implementations, generally used to indicate a method in which movement velocity or load is altered between sets and/or exercises within the same session with the aim of improving slow and fast force expression. We propose the following terminology for said implementations: contrast training-exercise sequence with alternating high-load and low-load (higher-velocity) exercises in a set-by-set fashion within the same session (corresponding with 'contrast pairs' and 'intra-contrast rest'); descending training-several sets of high-load (e.g., back squat) exercises completed before the execution of several sets of low-load, higher-velocity (e.g., vertical jump) exercises within the same session; ascending training-several sets of low-load, higher-velocity exercises completed before several sets of high-load exercises within the same session; and French contrast training-subset of contrast training in which a series of exercises are performed in sequence within a single session: heavy compound exercise, plyometric exercise, light-to-moderate load compound exercise that maximises movement speed (i.e., external power), and a plyometric exercise (often assisted). Finally, practical applications and training considerations are presented.

Rate of Force Development Adaptations After Weightlifting-Style Training: The Influence of Power Clean Ability

ABSTRACT

James, LP, Suchomel, TJ, Comfort, P, Haff, GG, and Connick, M. Rate of force development adaptations after weightlifting-style training: the influence of power clean ability. J Strength Cond Res 36(6): 1560-1567, 2022-This experiment examined changes to the rate of force development (RFD) expressed under loaded jump conditions between individuals with a higher (stronger) and lower (weaker) weightlifting performance (as assessed by the 1 repetition maximum [RM] power clean) after training with the weightlifting derivatives. Two groups of markedly different weightlifting ability undertook 10 weeks of training with the power clean variants, snatch pulls, and jump squats across heavy and light conditions. Testing was performed at baseline, after 5 weeks of training (mid-test) and after training (post-test). During testing, RFD was assessed under a series of loads (20-80% squat 1RM) through the jump squat. Furthermore, the force-velocity relationship, and unloaded jump strategy (through the force-time curve waveform), were also examined. Very large change (Hedge's g, 95% confidence interval [g] = 2.10, 1.24 to 4.16) in RFD at 20% 1RM at mid-test occurred within the stronger group. Conversely, a small increase (g = 0.27, 0.53-1.91) among the weaker subjects existed in this measure at mid-test, reaching a moderate increase at post-test (g = 0.71, -0.18 to 2.15). Limited improvements were seen by the stronger subjects in RFD at 60 and 80% 1RM at either mid-test (60%: g = 0.27, -0.75 to 1.33; 80% = 0.02, -1.01 to 1.00) or post-test (60%: g = 0.52, -0.38 to 1.80; 80% = -0.26, -1.23 to 0.77). The stronger group experienced a shift throughout the force-velocity relationship while a more force-dominant adaptation occurred in weaker subjects. Differences in jump strategy between groups were also noted. Such training will elicit practically different adaptations in rapid force production depending on the individual's baseline weightlifting ability.

Practices of Strength and Conditioning Coaches: A Snapshot From Different Sports, Countries, and Expertise Levels

ABSTRACT

Weldon, A, Duncan, MJ, Turner, A, LaPlaca, D, Sampaio, J, and Christie, CJ. Practices of strength and conditioning coaches: a snapshot from different sports, countries, and expertise levels. J Strength Cond Res 36(5): 1335-1344, 2022-This study describes the practices of strength and conditioning coaches (SCCs) from different sports, countries, and expertise levels. One hundred fifty-six SCCs (31.9 ± 8.9 years old) completed an online survey, consisting of 40 questions (36 fixed response and 4 open-ended), with 8 sections as follows: (a) background information, (b) muscular strength and power development, (c) speed development, (d) plyometrics, (e) flexibility development, (f) physical testing, (g) technology use, and (h) programming and any additional comments. Responses were received from 48 sports and 17 countries. This study provides exploratory evidence incorporating responses primarily in soccer (45%), track and field (30%), volleyball (23%), golf (17%), and tennis (17%). A bachelor's degree or higher were held by 99% of SCCs, of which 94% were in a sports science-related field, and 71% held a strength and conditioning related certification or accreditation. Periodization strategies and physical testing were used by 96% and 94% of SCCs respectively. The hang clean (82%), power clean (76%), and clean high pull (63%) were the most prescribed Olympic weightlifting exercises. Multiple hops/lunges (84%) were the most prescribed plyometrics exercises. For open-ended questions, 40% of SCCs wanted to integrate more technology into their programs and 30% believed technology will be the main future trend. Strength and conditioning coaches from different sports, countries, and expertise levels can use the information presented in this study to review their current practices and provide a source of new ideas for diversifying or modifying future practices.

Acceleration Profiles and the Isoinertial Squatting Exercise: Is There a Direct Effect on Concentric-Eccentric Force, Power, and Neuromuscular Efficiency?

OBJECTIVE

To examine the selective influences of distinct acceleration profiles on the neuromuscular efficiency, force, and power during concentric and eccentric phases of isoinertial squatting exercise.

DESIGN

Cross-sectional study.

SETTING

Biomechanics laboratory of the university.

PARTICIPANTS

A total of 38 active adults were divided according to their acceleration profiles: higher (n = 17; >2.5 m/s2) and lower acceleration group (n = 21; <2.5 m/s2).

INTERVENTION

All subjects performed squats until failure attached to an isoinertial conic pulley device monitored by surface electromyography of rectus femoris, vastus medialis, vastus lateralis, biceps femoris, and semitendinosus.

MAIN OUTCOME MEASURES

An incremental optical encoder was used to assess maximal and mean power and force during concentric and eccentric phases. The neuromuscular efficiency was calculated using the mean force and the electromyographic linear envelope.

RESULTS

Between-group differences were observed for the maximal and mean force (Prange = .001-.005), power (P = .001), and neuromuscular efficiency (Prange = .001-.03) with higher significant values for the higher acceleration group in both concentric and eccentric phases.

CONCLUSION

Distinct acceleration profiles affect the neuromuscular efficiency, force, and power during concentric and eccentric phases of isoinertial squatting exercise. To ensure immediate higher levels of power and force output without depriving the neuromuscular system, acceleration profiles higher than 2.5 m/s2 are preferable. The acceleration profiles could be an alternative to evolve the isoinertial exercise.

No differences in weightlifting overhead pressing exercises kinetics

This study aimed to compare the kinetics between the push press (PP), push jerk (PJ), and split jerk (SJ). Sixteen resistance-trained participants (12 men and 4 women; age: 23.8 ± 4.4 years; height: 1.7 ± 0.1 m; body mass: 75.7 ± 13.0 kg; weightlifting experience: 2.2 ± 1.3 years; one repetition maximum [1RM] PP: 76.5 ± 19.5 kg) performed 3 repetitions each of the PP, PJ, and SJ at a relative load of 80% 1RM PP on a force platform. The kinetics (peak and mean force, peak and mean power, and impulse) of the PP, PJ, and SJ were determined during the dip and thrust phases. Dip and thrust displacement and duration were also calculated for the three lifts. In addition, the inter-repetition reliability of each variable across the three exercises was analysed. Moderate to excellent reliability was evident for the PP (Intraclass correlation coefficient [ICC] = 0.91-1.00), PJ (ICC = 0.86-1.00), and SJ (ICC = 0.55-0.99) kinetics. A one-way analysis of variance revealed no significant or meaningful differences (p > 0.05, η2 ≤ 0.010) for any kinetic measure between the PP, PJ, and SJ. In conclusion, there were no differences in kinetics between the PP, PJ, and SJ when performed at the same standardised load of 80% 1RM PP.

Postactivation performance enhancement (PAPE) of sprint acceleration performance

Postactivation performance enhancement (PAPE) is a principle that an acute bout of high-intensity voluntary exercise is followed by an enhancement in strength, speed or power production. This study intended to show a direct correlation between intensity, specificity and the outcome of a maximal task of sprint accelerations compared to a previously defined weighted plyometric intervention. In a randomised controlled, double-blind trial, professional footballers undertook 20 m maximal sprint accelerations at a baseline and at 2 and 6 min post-intervention after 1 of 3 interventions; 2 repetitions of 20 m sprint accelerations (S), 3 × 10 alternative leg weighted bounding (P) and control (C). Relative to the baseline there was a significant improvement for S over 10 and 20 m at 2 min of 0.12m.s^-1 and 0.11m.s^-1 and 6 min of 0.11m.s^-1 and 0.12m.s^-1. Relative to the baseline P also had a significant improvement over 10 and 20 m at 2 min 0.09m.s^-1 and 0.09m.s^-1 and 6 min of 0.11m.s^-1 and 0.09m.s^-1. There was a significant improvement in C between 2 and 6 min post-intervention at 10 and 20 m of 0.06m.s^-1 and 0.08m.s^-1. This finding suggests a maximal sprint acceleration may enhance the outcome of a subsequent maximal sprint acceleration at 2 min, but the latter results could not be directly attributed to the interventions as previous testing is likely to have influenced these outcomes.

A systematic review of resistance training methodologies for the development of lower body concentric mean power, peak power, and mean propulsive power in team-sport athletes

This study aimed to systematically review training methods prescribed to develop lower-body power, determine their effectiveness for the development of lower-body mechanical power and their implementation in an annual training cycle amongst team-sport athletes. The absolute and relative outcome values of concentric mean power, peak power and mean propulsive power were extracted from 19 studies. Outcomes were assessed using baseline to post intervention percent change, effect sizes, and the level of evidence concerning the method's effectiveness. A thorough analysis of the literature indicated that, based on the high level of evidence, traditional (e.g., strength training alone) and combination training (e.g., complex and contrast) methods should be considered. Further, optimal load and velocity-based training can be implemented if coaches have access to the appropriate equipment to monitor movement velocity and mechanical power in every session. This is of particular importance in periods of the season where high volumes of technical-tactical training and congested fixture periods are present. Also, flywheel, eccentric overload and weightlifting methods have been shown to be effective although the level of evidence is low. Future research should expand on current training practices whilst adequately reporting actual training loads from sport-specific training and games alongside strength-power training protocols.

The effect of load based on body mass percentage on peak power output in the hang power clean, hang high pull, and mid-thigh clean pull

BACKGROUND

Prescribing load at the peak power output (PPO) is one of the strategies utilized to enhance lower-body muscle power. PPO of an exercise is determined based on a relative percentage of the one-repetition maximum test (1RM). However, 1RM tests may be impractical in some weightlifting derivatives. This study aimed to identify the PPO of the hang power clean (HPC), hang high pull (HHP), and mid-thigh clean pull (MTCP) based on a relative percentage of body mass (BM).

METHODS

Fifteen males with weightlifting experience performed HPC, HHP, and MTCP at loads ranging from 30-90% BM. Kinematic data were collected through a 16-camera infrared motion capture system and processed based on a 3-dimensional lower-extremity model. Ground reaction force (GRF) data were collected from two force plates. PPO was calculated as the product of model center of mass velocity and combined vertical GRF during the concentric phase.

RESULTS

PPO occurred at 90% BM for the HPC. In addition, the PPO occurred at 90% BM for the HHP and it was not different than 70 and 80% BM. At last, the PPO for MTCP occurred at 80% BM and it was not different than 60 and 70% BM.

CONCLUSIONS

Relative percentages of BM can be used to determine PPO in the HPC, HHP, and MTCP. PPO during HPC is achieved at 90% BM, while the PPO for HHP and MTCP is achieved between 70 to 90% BM and 60 to 80% BM, respectively.

Training for Muscular Strength: Methods for Monitoring and Adjusting Training Intensity

Linear loading, the two-for-two rule, percent of one repetition maximum (1RM), RM zones, rate of perceived exertion (RPE), repetitions in reserve, set-repetition best, autoregulatory progressive resistance exercise (APRE), and velocity-based training (VBT) are all methods of adjusting resistance training intensity. Each method has advantages and disadvantages that strength and conditioning practitioners should be aware of when measuring and monitoring strength characteristics. The linear loading and 2-for-2 methods may be beneficial for novice athletes; however, they may be limited in their capacity to provide athletes with variation and detrimental if used exclusively for long periods of time. The percent of 1RM and RM zone methods may provide athletes with more variation and greater potential for strength-power adaptations; however, they fail to account for daily changes in athlete's performance capabilities. An athlete's daily readiness can be addressed to various extents by both subjective (e.g., RPE, repetitions in reserve, set-repetition best, and APRE) and objective (e.g., VBT) load adjustment methods. Future resistance training monitoring may aim to include a combination of measures that quantify outcome (e.g., velocity, load, time, etc.) with process (e.g., variability, coordination, efficiency, etc.) relevant to the stage of learning or the task being performed. Load adjustment and monitoring methods should be used to supplement and guide the practitioner, quantify what the practitioner 'sees', and provide longitudinal data to assist in reviewing athlete development and providing baselines for the rate of expected development in resistance training when an athlete returns to sport from injury or large training load reductions.

Comparison of Joint Work During Load Absorption Between Weightlifting Derivatives

ABSTRACT

Suchomel, TJ, Giordanelli, MD, Geiser, CF, and Kipp, K. Comparison of joint work during load absorption between weightlifting derivatives. J Strength Cond Res 35(2S): S127-S135, 2021-This study examined the lower-extremity joint-level load absorption characteristics of the hang power clean (HPC) and jump shrug (JS). Eleven Division I male lacrosse players were fitted with 3-dimensional reflective markers and performed 3 repetitions each of the HPC and JS at 30, 50, and 70% of their 1 repetition maximum (1RM) HPC while standing on force plates. Load absorption joint work and duration at the hip, knee, and ankle joints were compared using 3-way repeated-measures mixed analyses of variance. Cohen's d effect sizes were used to provide a measure of practical significance. The JS was characterized by greater load absorption joint work compared with the HPC performed at the hip (p < 0.001, d = 0.84), knee (p < 0.001, d = 1.85), and ankle joints (p < 0.001, d = 1.49). In addition, greater joint work was performed during the JS compared with the HPC performed at 30% (p < 0.001, d = 0.89), 50% (p < 0.001, d = 0.74), and 70% 1RM HPC (p < 0.001, d = 0.66). The JS had a longer loading duration compared with the HPC at the hip (p < 0.001, d = 0.94), knee (p = 0.001, d = 0.89), and ankle joints (p < 0.001, d = 0.99). In addition, the JS had a longer loading duration compared with the HPC performed at 30% (p < 0.001, d = 0.83), 50% (p < 0.001, d = 0.79), and 70% 1RM HPC (p < 0.001, d = 0.85). The JS required greater hip, knee, and ankle joint work on landing compared with the load absorption phase of the HPC, regardless of load. The HPC and JS possess unique load absorption characteristics; however, both exercises should be implemented based on the goals of each training phase.

Strength, Endocrine, and Body Composition Alterations across Four Blocks of Training in an Elite 400 m Sprinter

The ability to produce force rapidly has the potential to directly influence sprinting performance through changes in stride length and stride frequency. This ability is commonly referred to as the rate of force development (RFD). For this reason, many elite sprinters follow a combined program consisting of resistance training and sprint training. The purpose of this study was to investigate the strength, endocrine and body composition adaptations that occur during distinct phases of a block periodized training cycle in a 400 m Olympic level sprinter. The athlete is an elite level 400 m male sprinter (age 31 years, body mass: 74 kg, years of training: 15 and Personal Best (PB): 45.65 s). This athlete completed four distinct training phases of a block periodized training program (16 weeks) with five testing sessions consisting of testosterone:cortisol (T/C) profiles, body composition, vertical jump, and maximum strength testing. Large fluctuations in T/C were found following high volume training and the taper. Minor changes in body mass were observed with an abrupt decrease following the taper which coincided with a small increase in fat mass percentage. Jump height (5.7%), concentric impulse (9.4%), eccentric impulse (3.4%) and power ratio (18.7%) all increased substantially from T1 to T5. Relative strength increased 6.04% from T1 to T5. Lastly, our results demonstrate the effectiveness of a competitive taper in increasing physiological markers for performance as well as dynamic performance variables. Block periodization training was effective in raising the physical capabilities of an Olympic level 400 m runner which have been shown to directly transfer to sprinting performance.

Comparison of the Power Output Between the Hang Power Clean and Hang High Pull Across a Wide Range of Loads in Weightlifters

ABSTRACT

Takei, S, Hirayama, K, and Okada, J. Comparison of the power output between the hang power clean and hang high pull across a wide range of loads in weightlifters. J Strength Cond Res 35(2S): S84-S88, 2021-The current study compared the peak power output during the hang power clean (HPC) and hang high pull (HHP) across a wide range of external loads in weightlifters. Eight weightlifters completed 1 repetition maximum (1RM) assessment for the HPC (1.59 ± 0.17 kg/body mass) and a power test for the HPC and HHP at relative loads of 40, 60, 70, 80, 90, 95, and 100% 1RM of the HPC. The ground reaction force and 2-dimensional bar position data were recorded to determine the system (barbell + body mass) kinetics and bar height, respectively. System power was calculated as force multiplied by system velocity. The HHP produced significantly greater peak power than the HPC at 40, 60, and 70% 1RM. Conversely, there was no statistical or practical difference in peak power between the exercises at 80, 90, 95, and 100% 1RM. No significant interaction was found in force at peak power, whereas velocity at peak power was significantly greater during the HHP than during the HPC at 40, 60, and 70% 1RM. In addition, significantly greater peak bar height was observed for the HHP than the HPC at 40, 60, and 70% 1RM. From the power output comparisons across loads, the HHP should be used over the HPC at loads of 40-70% 1RM, whereas the HPC and HHP can be interchangeably used at loads of 80-100% 1RM.

The Validity and Reliability of Commercially Available Resistance Training Monitoring Devices: A Systematic Review

Background

Monitoring resistance training has a range of unique difficulties due to differences in physical characteristics and capacity between athletes, and the indoor environment in which it often occurs. Traditionally, methods such as volume load have been used, but these have inherent flaws. In recent times, numerous portable and affordable devices have been made available that purport to accurately and reliably measure kinetic and kinematic outputs, potentially offering practitioners a means of measuring resistance training loads with confidence. However, a thorough and systematic review of the literature describing the reliability and validity of these devices has yet to be undertaken, which may lead to uncertainty from practitioners on the utility of these devices.

Objective

A systematic review of studies that investigate the validity and/or reliability of commercially available devices that quantify kinetic and kinematic outputs during resistance training.

Methods

Following PRISMA guidelines, a systematic search of SPORTDiscus, Web of Science, and Medline was performed; studies included were (1) original research investigations; (2) full-text articles written in English; (3) published in a peer-reviewed academic journal; and (4) assessed the validity and/or reliability of commercially available portable devices that quantify resistance training exercises.

Results

A total of 129 studies were retrieved, of which 47 were duplicates. The titles and abstracts of 82 studies were screened and the full text of 40 manuscripts were assessed. A total of 31 studies met the inclusion criteria. Additional 13 studies, identified via reference list assessment, were included. Therefore, a total of 44 studies were included in this review.

Conclusion

Most of the studies within this review did not utilise a gold-standard criterion measure when assessing validity. This has likely led to under or overreporting of error for certain devices. Furthermore, studies that have quantified intra-device reliability have often failed to distinguish between technological and biological variability which has likely altered the true precision of each device. However, it appears linear transducers which have greater accuracy and reliability compared to other forms of device. Future research should endeavour to utilise gold-standard criterion measures across a broader range of exercises (including weightlifting movements) and relative loads.

Electronic supplementary material

The online version of this article (10.1007/s40279-020-01382-w) contains supplementary material, which is available to authorized users.

Association of Jumping Ability and Maximum Strength With Dive Distance in Swimmers

PURPOSE

The aim of the current study was to investigate the relationship between dive distance (DD) and countermovement jump (CMJ) height, track start CMJ height, countermovement broad jump (CMBJ) distance, track start broad jump distance, and isometric midthigh pull peak force and relative peak force.

METHODS

A total of 27 (11 female and 16 male) regional-national-international-standard swimmers (mean [SD]; age = 19.5 [5.5] y; mass = 69.3 [10.5] kg; height = 1.77 [0.09] m) performed 3 trials of a track start dive, CMJ, track start CMJ, CMBJ, track start broad jump, and isometric midthigh pull.

RESULTS

Data were separated into pooled (females and males combined), females, and males. Large to very large correlations were found between DD and all variables tested for pooled data (r = .554-.853, P < .001-.008), with DD-CMBJ displaying the highest correlation (r = .853, P < .001). CMBJ accounted for 70% of the variance in DD. Females demonstrated moderate nonsignificant correlations between DD isometric midthigh pull (r = .379, P < .125). Males demonstrated very large significant correlations between DD-CMJ (r = .761, P < .001).

CONCLUSIONS

DD demonstrated strong correlations with jump performances and multijoint isometric force production in pooled data. Males showed stronger correlations than females due to being stronger and being able to perform the jumping/strength tasks to a higher standard. Enhanced jump performance and increased maximal force production may, therefore, enhance DD in swimmers.

A Comparison of Kinetic and Kinematic Variables During the Midthigh Pull and Countermovement Shrug, Across Loads

Meechan, D, Suchomel, TJ, McMahon, JJ, and Comfort, P. A comparison of kinetic and kinematic variables during the midthigh pull and countermovement shrug, across loads. J Strength Cond Res 34(7): 1830-1841, 2020-This study compared kinetic and kinematic variables during the midthigh pull (MTP) and countermovement shrug (CMS). Eighteen men (age: 29.43 ± 3.95 years, height: 1.77 ± 0.08 m, body mass: 84.65 ± 18.79 kg, and 1 repetition maximum [1RM] power clean: 1.02 ± 0.18 kg·kg) performed the MTP and CMS at intensities of 40, 60, 80, 100, 120, and 140% 1RM, in a progressive manner. Peak force (PF), mean force (MF), peak velocity, peak barbell velocity (BV), peak power, (PP), mean power (MP), and net impulse were calculated from force-time data during the propulsion phase. During the CMS, PF and MF were maximized at 140% 1RM and was significantly greater than the MTP at all loads (p ≤ 0.001, Hedges g = 0.66-0.90); p < 0.001, g = 0.74-0.99, respectively). Peak velocity and BV were significantly and meaningfully greater during the CMS compared with the MTP across all loads (p < 0.001, g = 1.83-2.85; p < 0.001, g = 1.73-2.30, respectively). Similarly, there was a significantly and meaningfully greater PP and MP during the CMS, across all loads, compared with the MTP (p < 0.001, g = 1.45-2.22; p < 0.001, g = 1.52-1.92). Impulse during the CMS was also significantly greater across all loads (p < 0.001, g = 1.20-1.66) compared with the MTP. Results of this study demonstrate that the CMS may be a more advantageous exercise to perform to enhance force-time characteristics when compared with the MTP, due to the greater kinetics and kinematic values observed.

A Comparison of Kinetic and Kinematic Variables During the Pull From the Knee and Hang Pull, Across Loads

Meechan, D, McMahon, JJ, Suchomel, TJ, and Comfort, P. A comparison of kinetic and kinematic variables during the pull from the knee and hang pull, across loads. J Strength Cond Res 34(7): 1819-1829, 2020-Kinetic and kinematic variables during the pull from the knee (PFK) and hang pull (HP) were compared in this study. Eighteen men (age = 29.43 ± 3.95 years; height 1.77 ± 0.08 m; body mass 84.65 ± 18.79 kg) performed the PFK and HP with 40, 60, 80, 100, 120, and 140% of 1-repetition maximum (1RM) power clean, in a progressive manner. Peak force (PF), mean force (MF), peak system velocity (PSV), mean system velocity (MSV), peak power (PP), mean power (MP), and net impulse were calculated from force-time data during the propulsion phase. During the HP, small-to-moderate yet significantly greater MF was observed compared with the PFK, across all loads (p ≤ 0.001; Hedges g = 0.47-0.73). Hang pull PSV was moderately and significantly greater at 100-140% 1RM (p = 0.001; g = 0.64-0.94), whereas MSV was significantly greater and of a large-to-very large magnitude compared with PFK, across all loads (p < 0.001; g = 1.36-2.18). Hang pull exhibited small to moderate and significantly greater (p ≤ 0.011, g = 0.44-0.78) PP at 100-140%, with moderately and significantly greater (p ≤ 0.001, g = 0.64-0.98) MP across all loads, compared with the PFK. Hang pull resulted in a small to moderate and significantly greater net impulse between 100 and 140% 1RM (p = 0.001, g = 0.36-0.66), compared with PFK. The results of this study demonstrate that compared with the PFK, the HP may be a more beneficial exercise to enhance force-time characteristics, especially at loads of ≥1RM.

Training With Weightlifting Derivatives: The Effects of Force and Velocity Overload Stimuli

Suchomel, TJ, McKeever, SM, and Comfort, P. Training with weightlifting derivatives: The effects of force and velocity overload stimuli. J Strength Cond Res 34(7): 1808-1818, 2020-The purposes of this study were to compare the training effects of weightlifting movements performed with (CATCH) or without (PULL) the catch phase of clean derivatives performed at the same relative loads or training without the catch phase using a force- and velocity-specific overload stimulus (OL) on isometric and dynamic performance tasks. Twenty-seven resistance-trained men completed 10 weeks of training as part of the CATCH, PULL, or OL group. The CATCH group trained using weightlifting catching derivatives, while the PULL and OL groups used biomechanically similar pulling derivatives. The CATCH and PULL groups were prescribed the same relative loads, while the OL group was prescribed force- and velocity-specific loading that was exercise and phase specific. Preintervention and postintervention isometric midthigh pull (IMTP), relative one repetition maximum power clean (1RM PC), 10-, 20-, and 30-m sprint, and 505 change of direction on the right (505R) and left (505L) leg were examined. Statistically significant differences in preintervention to postintervention percent change were present for relative IMTP peak force, 10-, 20-, and 30-m sprints, and 505L (all p < 0.03), but not for relative 1RM PC or 505R (p > 0.05). The OL group produced the greatest improvements in each of the examined characteristics compared with the CATCH and PULL groups with generally moderate to large practical effects being present. Using a force- and velocity-specific overload stimulus with weightlifting pulling derivatives may produce superior adaptations in relative strength, sprint speed, and change of direction compared with submaximally loaded weightlifting catching and pulling derivatives.

A new training method for leg explosive power in taekwondo and its data-driven predictive models

BACKGROUND: Kicking is the major way to score in a Taekwondo competition, which makes athletes’ leg power a key quality. However, the characteristics of leg power are very complex and it is difficult to generate physical models to predict training performance. OBJECTIVE: To study training programmes of leg power for Taekwondo using data-driven techniques in correlation analyses and modelling. METHODS: An 8-week program for back squat training was performed using two devices, a Cormax training system and a conventional barbell. Data analysis was conducted to identify the factors affecting the explosive power training. Finally, a data-driven modelling paradigm employing fuzzy rule-based systems was developed to predict the training performance. RESULTS: The Cormax system performed better in improving athletes’ maximum power and velocity. Maximum leg power was best correlated with athletes’ height. The developed predictive models showed good accuracy despite possession of limited training data. CONCLUSIONS: This study demonstrated some new training devices which could greatly improve power training. Moreover, a state-of-the-art modelling strategy was able to construct accurate models for training and exercise performance. The predictive models will likely enhance the anticipation of training outcome in advance which may assist in formulating and improving the training programmes.

Spanish Costaleros' Physical Activity and Their Quality of Life

(1) Physical activity is one of the most influencing factors in people’ quality of life. Likewise, the costaleros of the Holy Week of Andalusia (Spain) carry out an important effort with high intensity during an extended time without any preparation. This study was the aim of knowing the intensity of the physical activity practiced by the costaleros in relation to their quality of life. (2) A transversal study was carried out with 1057 costaleros in Andalusia (Spain), where 930 were male and 127 female, between the ages of 18–61 years old (31.26 ± 7.60). For this purpose, descriptive, inferential, and correlative analyses were developed. Accelerometers (ActiGraph) were used during the procession to know the intensity of physical activity and the SF-36 test to know the self-perceived state of health and quality of life. (3) The intensity of physical activity practiced by costaleros is moderate, and it is related with their quality of life. In addition, positive associations are found between general health and physical activity. (4) Participants’ quality of life is associated with physical activity and freedom from injury. In addition, the measurement by accelerometry provides real data on the intensity of the effort made.

A strength-oriented exercise session required more recovery time than a power-oriented exercise session with equal work

The present randomized cross-over controlled study aimed to compare the rate of recovery from a strength-oriented exercise session vs. a power-oriented session with equal work. Sixteen strength-trained individuals conducted one strength-oriented session (five repetitions maximum (RM)) and one power-oriented session (50% of 5RM) in randomized order. Squat jump (SJ), countermovement jump (CMJ), 20-m sprint, and squat and bench press peak power and estimated 1RMs were combined with measures of rate of perceived exertion (RPE) and perceived recovery status (PRS), before, immediately after and 24 and 48 h after exercise. Both sessions induced trivial to moderate performance decrements in all variables. Small reductions in CMJ height were observed immediately after both the strength-oriented session (7 ± 6%) and power-oriented session (5 ± 5%). Between 24 and 48 h after both sessions CMJ and SJ heights and 20 m sprint were back to baseline. However, in contrast to the power-oriented session, recovery was not complete 48 h after the strength-oriented session, as indicated by greater impairments in CMJ eccentric and concentric peak forces, SJ rate of force development (RFD) and squat peak power. In agreement with the objective performance measurements, RPE and PRS ratings demonstrated that the strength-oriented session was experienced more strenuous than the power-oriented session. However, these subjective measurements agreed poorly with performance measurements at the individual level. In conclusion, we observed a larger degree of neuromuscular impairment and longer recovery times after a strength-oriented session than after a power-oriented session with equal total work, measured by both objective and subjective assessments. Nonetheless, most differences were small or trivial after either session. It appears necessary to combine several tests and within-test analyses (e.g., CMJ height, power and force) to reveal such differences. Objective and subjective assessments of fatigue and recovery cannot be used interchangeably; rather they should be combined to give a meaningful status for an individual in the days after a resistance exercise session.

Survey of Barbell Trajectory and Kinematics of the Snatch Lift from the 2015 World and 2017 Pan-American Weightlifting Championships

Analysis of elite performances is important to elucidate the characteristics of effective weightlifting technique contributing to the highest level of achievement. The general technique of the weightlifting movements is well established. However, it is also apparent that weightlifting technique can differ based on athlete characteristics. Thus, existing technical models may not accurately reflect current technique of top performers or be applied generically to athletes of different skill, size, sex, or ability. Therefore, the purpose of this descriptive study was to update the scientific knowledge of snatch technique of top international weightlifters. This study used video analysis to determine barbell trajectory and kinematics of 319 successful snatch attempts from two major international competitions. Relative frequencies of barbell trajectory types differed based on competition, sex, category, and ranking. No statistical differences were observed among the top-three performers for either sex for most kinematic variables, and there were no overall discernible patterns of effect size differences for individual or clusters of kinematic variables. The results of this study indicate that weightlifting success can be achieved with a variety of technique profiles.

Strength and Power Training in Rehabilitation: Underpinning Principles and Practical Strategies to Return Athletes to High Performance

Injuries have a detrimental impact on team and individual athletic performance. Deficits in maximal strength, rate of force development (RFD), and reactive strength are commonly reported following several musculoskeletal injuries. This article first examines the available literature to identify common deficits in fundamental physical qualities following injury, specifically strength, rate of force development and reactive strength. Secondly, evidence-based strategies to target a resolution of these residual deficits will be discussed to reduce the risk of future injury. Examples to enhance practical application and training programmes have also been provided to show how these can be addressed.