Comparison of Weightlifting, Traditional Resistance Training and Plyometrics on Strength, Power and Speed: A Systematic Review with Meta-Analysis

Identification of doping suspicions through artificial intelligence-powered analysis on athlete's performance passport in female weightlifting

Introduction

Doping remains a persistent concern in sports, compromising fair competition. The Athlete Biological Passport (ABP) has been a standard anti-doping measure, but confounding factors challenge its effectiveness. Our study introduces an artificial intelligence-driven approach for identifying potential doping suspicious, utilizing the Athlete's Performance Passport (APP), which integrates both demographic profiles and performance data, among elite female weightlifters.

Methods

Analyzing publicly available performance data in female weightlifting from 1998 to 2020, along with demographic information, encompassing 17,058 entities, we categorized weightlifters by age, body weight (BW) class, and performance levels. Documented anti-doping rule violations (ADRVs) cases were also retained. We employed AI-powered algorithms, including XGBoost, Multilayer Perceptron (MLP), and an Ensemble model, which integrates XGBoost and MLP, to identify doping suspicions based on the dataset we obtained.

Results

Our findings suggest a potential doping inclination in female weightlifters in their mid-twenties, and the sanctioned prevalence was the highest in the top 1% performance level and then decreased thereafter. Performance profiles and sanction trends across age groups and BW classes reveal consistently superior performances in sanctioned cases. The Ensemble model showcased impressive predictive performance, achieving a 53.8% prediction rate among the weightlifters sanctioned in the 2008, 2012, and 2016 Olympics. This demonstrated the practical application of the Athlete's Performance Passport (APP) in identifying potential doping suspicions.

Discussion

Our study pioneers an AI-driven APP approach in anti-doping, offering a proactive and efficient methodology. The APP, coupled with advanced AI algorithms, holds promise in revolutionizing the efficiency and objectivity of doping tests, providing a novel avenue for enhancing anti-doping measures in elite female weightlifting and potentially extending to diverse sports. We also address the limitation of a constrained set of APPs, advocating for the development of a more accessible and enriched APP system for robust anti-doping practices.

Physical and Physiological Characteristics of Elite CrossFit Athletes

Due to little available research on elite CrossFit athletes, the present investigation was undertaken to provide knowledge about their physical and physiological characteristics. Nineteen international level CrossFit athletes (8 men; 11 women) were tested for maximum oxygen consumption (V˙O2max), Wingate, squat 1 repetition maximum (1RM), countermovement jump (CMJ), lower body force-velocity, and body composition (DXA). To provide perspective, the results were compared to sixteen elite-level Alpinists (8 men; 8 women). There was no significant difference in absolute nor relative V˙O2max between the CrossFit and Alpinist men (p = 0.335 and p = 0.279, respectively). The CrossFit women showed similar absolute but higher relative V˙O2max than the Alpinist women (p = 0.055 and p = 0.005, respectively). Mean anaerobic power was higher in both CrossFit men and women (p = 0.021 and p = 0.008, respectively). There were no significant differences in squat 1RM and CMJ for both men and women (p > 0.05). Both CrossFit men and women showed lesser lower body force production (p = 0.043 and p = 0.034, respectively) but higher power (p = 0.009 and p = 0.003, respectively). The CrossFit men and women had a lower fat mass (p = 0.018 and p = 0.002, respectively) and fat percentage (p = 0.027 and p < 0.001, respectively). These observations show that elite CrossFit athletes possess physical and physiological characteristics comparable to world-class Alpinists.

Olympic Weightlifting Training for Sprint Performance in Athletes: A Systematic Review with Meta-analysis

This systematic review and meta-analysis aimed to determine whether Olympic weightlifting (OW) exercises would improve sprint performance when compared to a control intervention, (no training, standard sport-specific training, traditional resistance training, or plyometric training). Medline, Web of Science, SportDiscus, CINAHL, and Biological Science from inception to September 2022 was searched. Two authors independently selected the included studies, extracted data, and appraised the risk of bias. Certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation methodology. The primary meta-analysis combined the results of the sprint performance over the full length of each sprint test. The secondary meta-analyses combined the results of the sprint performance at 5, 10, and 20 m distance to capture information about the acceleration phase of the sprint tests. Eight studies with 206 athletes (female n=10, age range: 18.9-24.2 years) were identified. Sprint performance did not differ significantly comparing OW to the control intervention, nor at the full length (standardized mean difference=-0.07, 95% CI=-0.47 to 0.34, p=0.75, I2=46%) or during the acceleration phase (p≥0.26) of the sprint test. OW training does not improve sprint performance to a greater extent than comparator interventions.

Effects of chronic static stretching interventions on jumping and sprinting performance-a systematic review with multilevel meta-analysis

When improving athletic performance in sports with high-speed strength demands such as soccer, basketball, or track and field, the most common training method might be resistance training and plyometrics. Since a link between strength capacity and speed strength exists and recently published literature suggested chronic stretching routines may enhance maximum strength and hypertrophy, this review was performed to explore potential benefits on athletic performance. Based on current literature, a beneficial effect of static stretching on jumping and sprinting performance was hypothesized. A systematic literature search was conducted using PubMed, Web of Science and Google scholar. In general, 14 studies revealed 29 effect sizes (ES) (20 for jumping, nine for sprinting). Subgroup analyses for jump performance were conducted for short- long- and no stretch shortening cycle trials. Qualitative evaluation was supplemented by performing a multilevel meta-analysis via R (Package: metafor). Significant positive results were documented in six out of 20 jump tests and in six out of nine sprint tests, while two studies reported negative adaptations. Quantitative data analyses indicated a positive but trivial magnitude of change on jumping performance (ES:0.16, p = 0.04), while all subgroup analyses did not support a positive effect (p = 0.09-0.44). No significant influence of static stretching on sprint performance was obtained (p = 0.08). Stretching does not seem to induce a sufficient stimulus to meaningfully enhance jumping and sprinting performance, which could possibly attributed to small weekly training volumes or lack of intensity.

The Effects of Resistance Training on Sport-Specific Performance of Elite Athletes: A Systematic Review with Meta-Analysis

This systematic review examines the influence of resistance training (RT) on the performance outcomes of elite athletes. Adhering to PRISMA guidelines, a comprehensive search across PubMed, Scopus, SPORTDiscus, and Web of Science databases was conducted, considering studies up to November 19, 2023. The inclusion criteria were elite athletes involved in high-level competitions. Studies were categorized by the competitive level among elite athletes, athlete's sex, performance outcomes, and a training modality with subgroup analyses based on these factors. Thirty-five studies involving 777 elite athletes were included. The results of the meta-analysis revealed a large and significant overall effect of RT on sport-specific performance (standardized mean difference, SMD = 1.16, 95% CI: 0.65, 1.66), with substantial heterogeneity (I2 = 84%). Subgroup analyses revealed differential effects based on the competitive level, the type of sport-specific outcomes, and sex. National elite athletes showed more pronounced (large SMD) benefits from RT compared to international elite athletes (small SMD). Global outcomes revealed a medium but non-significant (p > 0.05) SMD, while local outcomes showed a large SMD. Notably, female athletes exhibited a large SMD, though not reaching statistical significance (p > 0.05), probably due to limited study participants. No significant (p > 0.05) differences were found between heavy and light load RT. Resistance training is effective in improving sport-specific performance in elite athletes, with its effectiveness modulated by the competitive level, the type of the performance outcome, and athlete's sex. The findings underscore the need for personalized RT regimens and further research, particularly in female elite athletes, as well as advanced RT methods for international elite athletes.

Pull-Up Performance Is Affected Differently by the Muscle Contraction Regimens Practiced during Training among Climbers

Sport climbing performance is highly related to upper limb strength and endurance. Although finger-specific methods are widely analyzed in the literature, no study has yet quantified the effects of arm-specific training. This study aims to compare the effects of three types of training involving different muscle contraction regimens on climbers' pull-up capabilities. Thirty advanced to high-elite climbers were randomly divided into four groups: eccentric (ECC; n = 8), isometric (ISO; n = 7), plyometric (PLYO; n = 6), and no specific training (CTRL; n = 9), and they participated in a 5-week training, twice a week, focusing on pull-ups on hangboard. Pre- and post-training assessments were conducted using a force-sensing hangboard, analyzing force, velocity, power, and muscle work during three pull-up exercises: pull-ups at body weight under different conditions, incremental weighted pull-ups, and an exhaustion test. The CTRL group showed no change. Maximum strength improved in all three training groups (from +2.2 ± 3.6% to +5.0 ± 2.4%; p < 0.001); velocity variables enhanced in the ECC and PLYO groups (from +5.7 ± 7.4 to +28.7 ± 42%; p < 0.05), resulting in greater power; amplitude increased in the ECC group; and muscle work increased in the PLYO group (+21.9 ± 16.6%; p = 0.015). A 5-week training period effectively enhanced arm performance, but outcomes were influenced by the chosen muscle contraction regimens and initial individual characteristics.

Resistance Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights (Part III)

In the final part of this three-article collection on the training strategies of Brazilian Olympic sprint and jump coaches, we provide a detailed description of the resistance training methods and exercises most commonly employed by these speed experts. Always with the objective of maximizing the sprint and jump capabilities of their athletes, these experienced coaches primarily utilize variable, eccentric, concentric, machine-based, isometric, complex, and isoinertial resistance training methods in their daily practices. Squats (in their different forms), Olympic weightlifting, ballistics, hip thrusts, lunges, calf raises, core exercises, leg curls, stiff-leg deadlifts, and leg extension are the most commonly prescribed exercises in their training programs, during both the preparatory and competitive periods. Therefore, the current manuscript comprehensively describes and examines these methods, with the additional aim of extrapolating their application to other sports, especially those where sprint speed is a key performance factor.

Plyometric Training's Effects on Young Male Karatekas' Jump, Change of Direction, and Inter-Limb Asymmetry

This study analysed the effects of performing a plyometric training programme on different types of jumping and specific changes of direction, and their respective asymmetries in karatekas. Twenty male karatekas (age 19 ± 4 years) were distributed in two groups, the control group (CG) and the experimental group (EG). The EG group (n = 10) performed a 6-week intervention of unilateral plyometric training, performing countermovement jumps (CMJ), drop jumps (DJ), and long jumps (SH). The tests performed at the beginning and at the end of the intervention were a unilateral and bilateral countermovement jump test (CMJ), single-leg hop test (SH), single-leg side-hop test (SSH), triple hop test (TH), and change of direction in a karate position test (MKUKS). The EG group obtained improvements in the CMJ with the stronger (p = 0.01; ES = 0.39) and weaker leg (p = 0.01; ES = 0.59), in the SH with the weaker leg (p = 0.01; ES = 0.45), in the SSH with the weaker leg (p = 0.03; ES = 0.33), in the MKUKS (p = 0.00; ES = 0.98), and improved the asymmetries obtained in the TH (p = 0.02; ES = -0.85). The GC group obtained significant differences in the CMJ with the stronger (p = 0.03; ES = 0.46) and weaker leg (p = 0.00; ES = 0.69), in the bilateral CMJ (p = 0.02; ES = 0.24), in the SH with the weaker leg (p = 0.00; ES = 0.34), in the TH with the stronger (p = 0.00; ES = -0.15) and weaker leg (p = 0.01; ES = 0.09), and in the MKUKS test (p = 0.04; ES = -0.94). A between-group analysis showed improvements of the EG over the GC in the TH with the stronger leg (p = 0.02; ES = 1.05). Performing plyometric training provides improvements in jumping, mainly in horizontal jumps, reducing inter-limb asymmetries in repetitive jumps.

Effects of plyometric training on measures of physical fitness in racket sport athletes: a systematic review and meta-analysis

Background

Over the past decade, the popularity of racket sports has surged. Plyometric training (PT) has been the focus of extensive research because of the proven benefits it provides to athletes. However, there is a lack of systematic reviews and meta-analyses specifically evaluating the impact of PT on physical fitness metrics in racket sport athletes. This study aimed to conduct a comprehensive review and analysis of evidence derived from randomized controlled trials (RCTs) to evaluate the effects of PT on measures of physical fitness among racket sports athletes.

Methods

The electronic databases PubMed, Web of Science, SCOPUS, and SPORTDiscus were systematically searched up to June 2023 without placing any restrictions on the publication dates. The PICOS method was adopted to establish the inclusion criteria: (a) healthy athletes who participate in racket sports; (b) a PT program; (c) a control group; (d) assessment of physical fitness components pre- and post-PT; and (e) RCTs. The records' methodological quality was assessed utilizing the Physiotherapy Evidence Database (PEDro) scale. The certainty in the evidence related to each outcome was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) assessment. A random-effects model was used to calculate effect sizes (ES; Hedges' g) between experimental and control groups.

Results

There were 14 eligible studies of moderate-to-high-quality, involving 746 athletes in total. The results revealed small-to-moderate effects (p < 0.05) of PT on muscle power (ES = 0.46), muscle strength (ES = 0.50), sprint speed (ES = 0.45), change of direction ability (ES = 0.76), and reaction time (ES = 0.67), while no clear evidence was found on balance and flexibility. The training-induced changes in muscle power showed no significant difference (p > 0.05) between youth (ES = 0.72) and adults (ES = 0.40). There were also similar muscle power improvements (ES = 0.36-0.54 vs 0.38-0.56, all p > 0.05) for a length of ≤7 weeks with ≤14 total PT sessions vs >7 weeks with >14 total PT sessions, and ≤2 weekly sessions vs >2 sessions. No adverse effects were reported in the included studies regarding the PT intervention. The certainty of evidence varied from very low to moderate. Conclusions: Our findings demonstrated that PT has positive effects on important indices of physical fitness among athletes participating in racket sports. Future studies are required to clarify the optimal doses and examine interactions among training variables to further promote the physical fitness of this specific population.

Effects of Expertise on Muscle Activity during the Hang Power Clean and Hang Power Snatch Compared to Snatch and Clean Pulls - An Explorative Analysis

The purpose was to compare the electromyographic (EMG) activity of the Hang Power Clean (HPC) and Hang Power Snatch (HPS) with the Hang Clean Pull (HCP) and Hang Snatch Pull (HSP). Additionally, the influence of weightlifting expertise (beginner, advanced and elite) on EMG activity was analyzed. Twenty-seven weightlifters (beginner: n = 11, age: 23.9 ± 3.2 years, bodyweight: 75.7 ± 10.5 kg; advanced: n = 10, age: 24.8 ± 4.5 years, bodyweight: 69.4 ± 13.9 kg; elite: n = 6, age: 25.5 ± 5.2 years, bodyweight: 75.5 ± 12.5 kg) participated in this study. Participants performed two repetitions of HPC, HPS, HCP, and HSP at 50%, 70%, and 90% 1RM, respectively. The EMG activity of vastus lateralis (VL), gluteus maximus (GM), erector spinae (ES), rectus abdominis (RA) and trapezius (TZ) was recorded and normalized to the maximum voluntary isometric contraction (MVIC) of each muscle. There were significant differences in RA and ES EMG activity at 70% and 90% 1RM during HPC compared to HCP in the beginner group (p < 0.05, Hedges g = 0.50-1.06). Significant greater ES activity was observed in the beginner, advanced, and elite groups (p < 0.05, g = 0.27-0.98) during the HPS when compared to the HSP at 50-90% 1RM. TZ muscle activity was significantly greater at 50% and 70% 1RM in the HCP compared to the HPC in the elite group (p < 0.05, g = 0.61-1.08), while the beginner group reached significance only at 50% 1RM favoring HPC (p < 0.05, g = 0.38). Moreover, the EMG activity of the TZ during the HSP and HPS was significantly different only at 50% 1RM in the elite group and favored HSP (p < 0.05, g = 0.27). No differences were observed between the levels of weightlifting expertise. Based upon the results of this study, the overall pattern of EMG activity of the predominant muscles involved in HPC/HPS and the corresponding weightlifting pulling derivatives, apart from the stabilizing muscle (RA and ES), is similar at higher intensities (>70% 1RM) and expertise does not influence muscle activity.

The efficacy of neuromuscular training, with minimal or no equipment, on performance of youth athletes: A systematic review with meta-analysis

OBJECTIVES

To investigate the effects of neuromuscular training, with minimal or no equipment, on physical performance of youth athletes.

DESIGN

Systematic review with meta-analysis.

METHODS

MEDLINE, EMBASE, CENTRAL, CINAHL, PEDro and SportDiscuss from inception to March/2022.

SELECTION CRITERIA

youth athletes (15-24years), from Olympic team sports; used neuromuscular training 2-3 times/week for, at least, 6 weeks; had a control group/usual training group; physical performance as outcomes; randomized controlled trial.

DATA SYNTHESIS

Pooled estimate of standardized mean difference (SMD), and 95% confidence interval (95%CI).

RESULTS

Thirty-four studies (1111 participants) were included. Results showed that neuromuscular training improved power (SMD: 0.84 [95%CI: 0.58, 1.10]; n = 805; I2 = 64%), speed (SMD: -1.12 [95%CI: -1.68, -0.57]; n = 688; I2 = 90%) and agility (SMD: -1.21 [95%CI: -1.60, -0.83]; n = 571; I2 = 76%) compared to control group, but showed no difference between groups for muscle strength (Quadriceps SMD: 0.34 [95%CI: -0.02, 0.69]; n = 132; I2 = 0%, Hamstrings: SMD: 0.64 [95%CI: -0.04, 1.33]; n = 132; I2 = 71%), balance and flexibility.

CONCLUSION

Clinically, neuromuscular training with minimal equipment may be useful for teams with limited resources to improve mainly athletes' power and agility, including those interventions that were designed to injury prevention. Future high-quality studies are likely to change these estimates.

Effects of physical training programs on female tennis players' performance: a systematic review and meta-analysis

Background: Tennis is among the world's most popular and well-studied sports. Physical training has commonly been used as an intervention among athletes. However, a comprehensive review of the literature on the effects of physical training programs on female tennis players' performance is lacking. Therefore, this systematic review and meta-analysis aimed to determine the effects of physical training on performance outcomes in female tennis players. Methods: A comprehensive search was conducted on Web of Science, PubMed, SPORTDicus, Scopus, and CNKI from inception until July 2023 to select relevant articles from the accessible literature. Only controlled trials were included if they examined the effects of physical training on at least one measure of tennis-specific performance in female tennis players. The Cochrane RoB tool was employed to assess the risk of bias. The CERT scale was used to examine the quality of program information. The GRADE approach was adopted to evaluate the overall quality of the evidence. The Comprehensive Meta-Analysis software was used for the meta-analysis. Results: Nine studies were selected for the systematic review and seven for the meta-analysis, totaling 222 individuals. The study's exercise programs lasted 6-36 weeks, with training sessions ranging from 30 to 80 min, conducted one to five times per week. Muscle power (ES = 0.72; p = 0.003), muscle strength (ES = 0.65; p = 0.002), agility (ES = 0.69; p = 0.002), serve velocity (ES = 0.72; p = 0.013), and serve accuracy (ES = 1.14; p = 0.002) demonstrated significant improvement following physical training, while no notable changes in linear sprint speed (ES = 0.63; p = 0.07) were detected. Conclusion: Although research on physical training in sports is diversified, studies on training interventions among female tennis players are scarce. This review found that existing training programs yield some favorable outcomes for female tennis players. However, further research with high methodological quality is warranted on the tailoring of specific training programs for female tennis players. There should be more consistent measuring and reporting of data to facilitate meaningful data pooling for future meta-analyses.

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.

Effectiveness of plyometric training vs. complex training on the explosive power of lower limbs: A Systematic review

Introduction: Explosive power is considered an important factor in competitive events. Thus, strategies such as complex training (CT) and plyometric training (PLT) are effective at improving explosive power. However, it is still not clear which of the two strategies can enable greater improvements on the explosive power. Thus, the aim of this systematic review was to compare the effects of PLT and CT on the explosive power of the lower limbs. Methods: The Review Manager and GraphPad Prism programs were used to analyze the synthetic and time effects (effects over training time) on explosive power (i.e., jump ability, sprint ability) and maximum strength. Our research identified 87 studies comprising 1,355 subjects aged 10-26.4 years. Results: The results suggested the following: 1) Synthetic effects on jump ability (Hedges' g): .79 (p < .001) for unloaded PLT, 1.35 (p < .001) for loaded PLT and .85 (p < .001) for CT; 2) Synthetic effects on sprint ability: .83 (p < .001) for unloaded PLT, -2.11 (p < .001) for loaded PLT and -.78 (p < .001) for CT; 3) Synthetic effects on maximum strength: .84 (p < .001) for loaded PLT and 1.53 (p < .001) for CT; 4) The time effects of unloaded PLT and CT on explosive power were similar, but the time effects of CT on maximum strength were obviously above that of PLT. Discussion: In conclusion, unloaded PLT and CT have a similar effect on explosive performance in the short term but loaded PLT has a better effect. The improvement of the maximum strength caused by CT was greater than that induced by PLT. In addition, more than 10 weeks of training may be more beneficial for the improvement of power. Therefore, for explosive power training, we suggest adopting unloaded or light-loaded PLT during a short season and applying CT during an annual or long training cycle.

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.

Long-Term Changes in Vertical Jump, H:Q Ratio and Interlimb Asymmetries in Young Female Volleyball Athletes

The present study aimed to examine the changes that occurred in vertical jump and isokinetic dynamometer (ISK) performances at the beginning of a preparatory period (PRE) and at the start of the competitive period (POST). Sixteen U-17 elite female volleyball players, from a national level (15.34 ± 1.19 years; 66.35 ± 7.95 kg; 169.22 ± 24.79 cm), performed bilateral squat jump (SJ), bilateral and unilateral countermovement jump (CMJ) and unilateral ISK tests for knee flexors (Fl) and extensors (Ex) both at 60°/s and at 300°/s. Peak torque (PT) and the hamstring-to-quadriceps (H:Q) ratio were assessed by concentric actions. Asymmetries were calculated by the percentage differences between dominant (DOM) and nondominant legs (NDOM). The paired Student's t-test was used for comparisons at a level of significance of 5%. The effect size was also calculated. A significant increase was found for both SJ (15%; p = 0.004; ES = 0.82) and CMJ (12%; p = 0.017; ES = 0.62). The PT of NDOM flexors at 60°/s was significantly lower than DOM both at PRE (4.6%; p = 0.048; ES = -0.22) and POST (6.3%; p = 0.037; ES = -0.33). The NDOM extensors at 60°/s had a significantly lower PT than DOM at POST (7.0%; p = 0.048; ES = -0.23). Both DOM and NDOM flexors at 60°/s had a PT enhancement at POST related to PRE (6.7%; p = 0.031; ES = 0.51 and 5.6%; p = 0.037; ES = 0.48, respectively). The PT of NDOM extensors at 300°/s increased at POST in comparison to PRE (7.9%; p = 0.038; ES = 0.27). The NDOM at 300°/s had a H:Q ratio higher than DOM both in PRE and POST (8.6%; p = 0.041; ES = 0.37 and 11.6%; p = 0.013; ES = 0.71, respectively), and the highest H:Q ratios were lower than the reference values (<80%). The asymmetry of the unilateral CMJ was higher at POST than at PRE (102%; p = 0.03; ES = 0.81). The PT for the flexors at 300°/s and the H:Q ratio at POST exceeded 10%. In conclusion, a training program of 15 weeks increased the neuromuscular performance of young volleyball athletes, but many H:Q ratios and asymmetries remained out of the normal recommendation. Volleyball professionals should carefully apply an adequate training program to enhance physical fitness performance without increasing the risk of lower limb injuries concurrently.

Training Specificity for Athletes: Emphasis on Strength-Power Training: A Narrative Review

Specificity has two major components: A strength-endurance continuum (S-EC) and adherence to principles of Dynamic Correspondence. Available evidence indicates the existence of the S-EC continuum from two aspects. Indeed, the S-EC exists, particularly if work is equated as a high load low repetition scheme at one end (strength stimulus) and high volume (HIEE stimulus) at the other. Furthermore, some evidence also indicates that the continuum as a repetition paradigm with high-load, low repetition at one end (strength stimulus) and a high repetition, low load at the other end. The second paradigm is most apparent under three conditions: (1) ecological validity-in the real world, work is not equated, (2) use of absolute loads in testing and (3) a substantial difference in the repetitions used in training (for example 2-5 repetitions versus ≥10 repetitions). Additionally, adherence to the principles and criteria of dynamic correspondence allows for greater "transfer of training" to performance measures. Typically, and logically, in order to optimize transfer, training athletes requires a reasonable development of capacities (i.e., structure, metabolism, neural aspects, etc.) before more specific training takes place.

Not Another Caffeine Effect on Sports Performance Study-Nothing New or More to Do?

The performance-enhancing potential of acute caffeine consumption is firmly established with benefits for many aspects of physical performance and cognitive function summarised in a number of meta-analyses. Despite this, there remains near exponential growth in research articles examining the ergogenic effects of caffeine. Many such studies are confirmatory of well-established ideas, and with a wealth of convincing evidence available, the value of further investigation may be questioned. However, several important knowledge gaps remain. As such, the purpose of this review is to summarise key knowledge gaps regarding the current understanding of the performance-enhancing effect of caffeine and justify their value for future investigation. The review will provide a particular focus on ten research priorities that will aid in the translation of caffeine's ergogenic potential to real-world sporting scenarios. The discussion presented here is therefore essential in guiding the design of future work that will aid in progressing the current understanding of the effects of caffeine as a performance enhancer.

Experimental Study on the Effect of Speed Strength Training on the Special Strikes of Chinese Female Boxers

The aim of this study was to design a 12-week intervention experiment with a speed strength training program and conventional training to test and analyze the effects of speed strength training on punching speed, punching power, and punching effectiveness of female boxers and to provide empirical support for the targeted improvement of special striking effectiveness of female boxers. By using the experimental method, a controlled experiment was conducted with 20 athletes from the Chinese women’s boxing team as the study subjects, and the targeted experimental intervention was conducted. Through experiment, speed power training had no significant effect on the improvement of basic movement ability of female boxers. In addition, speed power training could effectively improve the speed power level of athletes in the experimental group, and the speed power level of the control group was not significantly improved. Lastly, speed power training improved the punching effect of the experimental group, and the effect of the control group was not significant. Conclusion of this study includes the following: (1) speed strength training improved the speed strength level of the athletes, but it did not have a significant effect on improving basic movement ability. (2) The improvement of speed strength could improve the striking speed of female boxers, and the speed strength training also achieved good results. (3) The improvement of speed strength had a positive effect on the special striking power of female boxers. (4) Speed strength training improved the special striking effect of female boxers athletes’ special hitting effect.

Resistance Training before, during, and after COVID-19 Infection: What Have We Learned So Far?

At the end of 2019, a severe acute respiratory syndrome caused by SARS-CoV-2 started a pandemic, leading to millions of deaths and many important political and social changes. Even in the absence of contamination, the mobility reduction, social distancing and closing of exercise facilities negatively affected physical activity and conditioning, which is associated with muscle atrophy, loss of muscle strength, and reductions in functional capacity. In cases of infection, it has been shown that increased physical capacity is associated with decreased hospitalization and mortality risk. Although millions of people have died from COVID-19, most contaminated individuals survived the infection, but carried different sequelae, such as the severe loss of physical function and a reduced quality of life. Among different physical exercise models that might help to prevent and treat COVID-19-related conditions, resistance training (RT) might be particularly relevant. Among its benefits, RT can be adapted to be performed in many different situations, even with limited space and equipment, and is easily adapted to an individual's characteristics and health status. The current narrative review aims to provide insights into how RT can be used in different scenarios to counteract the negative effects of COVID-19. By doing this, the authors expect to provide insights to help deal with the current pandemic and similar events the world may face in the future.

Effects of Different Hangboard Training Intensities on Finger Grip Strength, Stamina, and Endurance

Climbing-specific training programs on hangboards are often based on dead-hang repetitions, but little is known about the real intensity applied during such effort. The aim of this study was to quantify and compare the effects of different training intensities (maximal, high submaximal, and low submaximal intensities) on the fingers' physiological capabilities using a hangboard fitted with force sensors. In total, 54 experienced climbers (13 women and 41 men) were randomly divided into four groups, with each group following different training intensity programs: maximal strength program performed at 100% of the maximal finger strength (MFS; F100), intermittent repetitions at 80% MFS (F80), intermittent repetitions at 60% MFS (F60), and no specific training (control group). Participants trained on a 12 mm-deep hold, twice a week for 4 weeks. The MFS, stamina, and endurance levels were evaluated using force data before and after training. Results showed similar values in the control group between pre- and post-tests. A significantly improved MFS was observed in the F100 and F80 groups but not in the F60 group. Significantly higher stamina and endurance measurements were observed in the F80 and F60 groups but not in the F100 group. These results showed that a 4-week hangboard training enabled increasing MFS, stamina and endurance, and that different improvements occurred according to the level of training intensity. Interestingly, the different intensities allow improvements in the targeted capacity (e.g., stamina for the F80 group) but also in the adjacent physiological capabilities (e.g., MFS for the F80 group).