Age-effects of sport education model on basic psychological needs and intrinsic motivation of adolescent students: A systematic review and meta-analysis.

OBJECTIVE: This study explores the age effects of the sport education model(SEM) on the impact of basic psychological needs (autonomy, competence, relatedness) and intrinsic motivation (interest, enjoyment, satisfaction) among adolescent students. METHOD: Retrieval of relevant literature from PubMed, Web of Science, Scopus, and China National Knowledge Infrastructure (CNKI). The search period ranged from the starting year to January 7, 2024. Subsequently, literature screening, data extraction, and quality assessment will be conducted, and data analysis will be performed using "Review Manager 5.4" software. RESULT: Overall, SEM has a positive and statistically significant impact on the basic psychological needs (MD = 0.36,95% CI [0.22, 0.50]) and intrinsic motivation (MD = 0.75, 95% CI [0.58, 0.93]) of adolescent students (P<0.01). Subgroup analysis revealed age effects on the impact of SEM on the basic psychological needs of adolescent students: pre-peak height velocity (PRE-PHV) (MD = 0.39, 95% CI [0.23, 0.56], I2 = 45%, P<0.01), mid-peak height velocity (MID-PHV) (MD = 0.22, 95% CI [0.01, 0.42], I2 = 82%, P<0.05), post-peak height velocity (POST-PHV) (MD = 1.27, 95% CI [0.79, 1.74], I2 = 0%, P<0.01). Similarly, age effects were found for intrinsic motivation: MID-PHV (MD = 0.86, 95% CI [0.62, 1.11], I2 = 68%, P<0.01), POST-PHV (MD = 0.56, 95% CI [0.40, 0.72], I2 = 0%, P<0.01). CONCLUSION: The SEM is an effective approach to enhancing the basic psychological needs and intrinsic motivation of adolescent students. However, it exhibits age effects among students at different developmental stages. Specifically, in terms of enhancing basic psychological needs, the model has the greatest impact on POST-PHV students, followed by PRE-PHV students, while the improvement effect is relatively lower for MID-PHV students. The enhancement effect on intrinsic motivation diminishes with increasing age.

The enhancement of explosive power contributes to the development of anaerobic capacity: A comparison of autoregulatory progressive resistance exercise and velocity-based resistance training.

Objectives: Due to the character of the taekwondo, the adenosine triphosphate-phosphocreatine system provides the energy for each kick, the glycolytic system supports the repeated execution of kicks, and the aerobic system promotes recovery between these movements and the bout. Therefore, taekwondo athletes require high explosive power and anaerobic capacity in order to carry out sustained and powerful attacks. So, the purpose of this study is to compare the effects of APRE and VBRT on lower-limb explosive power and anaerobic capacity in college taekwondo players. Methods: A total of 30 taekwondo players completed an 8-week training intervention with autoregulatory progressive resistance exercise (APRE; n = 15) and velocity-based resistance training (VBRT; n = 15). Testing included the one-repetition maximum squat, countermovement jump (CMJ), taekwondo anaerobic intermittent kick test (TAIKT), and 30-s Wingate anaerobic test (WAnT). Results: (1) Intragroup comparisons revealed significant effects for one-repetition maximum squat, peak power of CMJ (CMJPP), relative peak power of CMJ (CMJRPP), and total number of TAIKT (TAIKTTN) in both the APRE and VBRT groups. The VBRT group exhibited small effect sizes for time at peak power of WAnT (WAnTPPT) and moderate effect sizes for peak power of WAnT (WAnTPP), relative peak power of WAnT (WAnTRPP), and fatigue index of TAIKT (TAIKTFI), whereas the APRE group exhibited small effect sizes for TAIKTFI. (2) Intergroup comparisons revealed no significant effects in any of the results. However, VBRT demonstrated a moderate advantage in WAnTPP and WAnTRPP, whereas APRE had a small advantage in CMJPP and CMJRPP. Conclusions: These findings suggest that APRE improved explosive power (CMJPP and CMJRPP) more, whereas VBRT improved anaerobic power output (WAnTPP and WAnTRPP) more. Both methods were found to have similar effects in improving the anaerobic endurance (WAnTPPT and TAIKTTN) and fatigue index (power drop of WAnT and TAIKTFI).

Effects of functional correction training on movement patterns and physical fitness in male college students.

The objective of this study is to investigate the effects of functional corrective training and static stretching on the quality of movement patterns and physical fitness in college students. The study was conducted with 30 male college students from a university in Guangzhou, China. The participants were randomly assigned to either the functional corrective training group (FCT, n = 15, age = 20.93 ± 0.85, BMI = 22.07 ± 2.33) or the static stretching group (SS, n = 13, age = 20.85 ± 0.86, BMI = 21.98 ± 1.80). Two participants from the SS group dropped out due to personal reasons, leaving 13 subjects in that group. Both groups underwent a 6-week training intervention, with sessions held twice a week. The FCT group participated in flexibility training, and/or static motor control training, and/or dynamic motor control training for 10-15 min. The SS group performed static stretching exercises targeting five specific muscles, with 30 s per side and two sets. The Functional Movement Screen (FMS), body composition, sit-and-reach, standing long jump, and pull-ups were assessed before and after the intervention. Differences in FMS outcomes were analyzed using two samples of the Mann-Whitney U test. Physical fitness outcomes were analyzed using a repeated measures analysis of variance (ANOVA) with a 2 (group) × 2 (time) design. After 6 weeks of intervention, the FCT group showed statistically significant improvements in the hurdle step (Z = -2.449, p = 0.014), inline lunge (Z = -2.000, p = 0.046), rotary stability (Z = -2.309, p = 0.021), and composite scores (Z = -3.316, p = 0.001). Comparisons between groups indicated that BMI (FCT, ES = 0.04; SS, ES = -0.11), 30-m sprint (FCT, ES = 0.12; SS, ES = 0.28), body fat percentage (BF%) (FCT, ES = -0.25; SS, ES = -0.07), and sit-and-reach (FCT, ES = 0.17; SS, ES = 0.06) were not statistically significant in both the pre- and post-tests. The effect sizes of all physical fitness indicators were greater in the FCT group than in the SS group. The FCT, consisting of two sessions per week for 6 weeks, has been proven to be effective in improving the quality of movement patterns by improved stability and advanced movements. However, the improvements in physical fitness did not reach statistical significance. FMS and FCT are generally affordable and accessible for college students. College students have the opportunity to employ the FMS tool to assess potential injury risks and address them, thereby reducing the risk of injuries.

Application of a New Monitoring Variable: Effects of Power Loss During Squat Training on Strength Gains and Sports Performance.

ABSTRACT: Zhang, M, Chen, L, Dai, J, Yang, Q, Huang, Z, He, J, Ji, H, Sun, J, and Li, D. Application of a new monitoring variable: Effects of power loss during squat training on strength gains and sports performance. J Strength Cond Res 38(4): 656-670, 2024-This study aimed to compare the effects of power loss (PL) autoregulated volume (PL10 and PL20) with standardized fixed-load (FL) prescription on strength, sports performance, and lean body mass (LBM). Thirty-five female basketball players from a sports college were randomly assigned to 3 experimental groups (PL10, n = 12; PL20, n = 12; and FL, n = 11, respectively) that performed a resistance training (RT) program with wave-like periodization for 10 weeks using the back squat exercise. Assessments performed before (Pre) and after (Post) intervention included assessed 1 repetition maximum (1RM), body composition, 20-m sprint (T20M), change of direction (COD), and jump performance, including countermovement jump with arm swing, maximum vertical jump, and reactive strength index. Three groups showed significant improvements in strength (effect size [ES]: PL10 = 2.98, PL20 = 3.14, and FL = 1.90; p < 0.001) and jump performance (ES: PL10 = 0.74, PL20 = 1.50, and FL = 0.50; p <0.05-0.001). However, PL10 and PL20 demonstrated different advantages in sports performance compared with FL (group × time interaction, p <0.05). Specifically, PL10 significantly improved COD performance (ES = -0.79 ∼ -0.53, p <0.01), whereas PL20 showed greater improvements in sprint (ES = -0.57, p <0.05) and jump performance (ES = 0.67-1.64, p <0.01-0.001). Moreover, PL10 resulted in similar gains to PL20 and beneficial improvements compared with FL in LBM, despite performing the least repetitions. Overall, the study indicates that power loss-based autoregulation induces greater gains in LBM and sports performance, as well as eliciting a higher efficiency dose response than standardized FL prescriptions, particularly for PL10. Therefore, incorporating PL monitoring in training programs is recommended, and further studies on power-based RT would be worthwhile.

Maximizing plyometric training for adolescents: a meta-analysis of ground contact frequency and overall intervention time on jumping ability: a systematic review and meta-analysis.

Plyometric training boosts adolescents' jumping ability, crucial for athletic success and health. However, the best total ground contact frequency (TGCF) and overall intervention time (OIT) for these exercises remain unclear. This meta-analysis aims to identify optimal TGCF and OIT in plyometric training for adolescents, focusing on countermovement jump (CMJ) and squat jump (SJ) outcomes. This systematic review encompassed five databases and included 38 studies with 50 randomized controlled experiments and 3347 participants. We used the Cochrane risk assessment tool for study quality and Review Manager 5.4 for data analysis. The current meta-analysis incorporated a total of 38 studies, comprising 50 sets of randomized controlled trials, to investigate the influence of different TGCFs and OITs on plyometric training. The Cochrane risk assessment tool indicated that all the included studies were classified as low risk. Various TGCFs in plyometric training positively affected CMJ and SJ heights in adolescents. The TGCF of less than 900 was ideal for enhancing CMJ, whereas more than 1400 was effective for SJ. The optimal OIT was 400-600 min, specifically, 500-600 min for CMJ and 400-500 min for SJ. Plyometric training improves jumping ability in adolescents. Lower ground contact frequency (< 900 contacts) enhances CMJ, while higher ground contact frequency (> 1400 contacts) is more effective for SJ. Optimal intervention time ranges from 400 to 600 min, with 500 to 600 min benefiting CMJ and 400 to 500 min improving SJ.

Comparing autoregulatory progressive resistance exercise and velocity-based resistance training on jump performance in college badminton athletes.

Objectives: Jumping ability has been identified as a key factor that influences the performance of badminton athletes. Autoregulatory progressive resistance exercise (APRE) and velocity-based resistance training (VBRT) are commonly used approaches to enhance muscle strength and have been shown to accurately monitor the development of explosive power to improve jumping ability. This study aims to investigate the effects of APRE and VBRT on badminton athletes' jumping ability and to provide practical insights into improving their jumping performance during competitions. Methods: Upon completing familiarization and pretesting, 18 badminton athletes were included and completed the training intervention (age, 21.4 ± 1.4 years; stature, 170.1 ± 7.3 cm; body mass, 65.9 ± 12 kg); they were randomly divided into the APRE group (n = 9) and VBRT group (n = 9). Jumping performance was assessed during the countermovement jump (CMJ), squat jump (SJ), and drop jump (DJ) via SmartJump, with CMJ 's and SJ's jump height, eccentric utilization ratio (EUR), and reactive strength index (RSI). All participants then completed a 4-week in-season resistance training intervention. Results: (1) The results of the within-group indicated that only the CMJ (pre: 41.56 ± 7.84 vs post: 43.57 ± 7.85, p < 0.05) of the APRE group had significant differences, whereas the SJ, EUR, and RSI were not significantly different (p > 0.05). (2) The results of the intergroups revealed that all indicators had no significant differences (p > 0.05), but APRE had a moderate effect size on the improvement of the CMJ (η2 = 0.244) and EUR (η2 = 0.068) when compared with VBRT. Conclusions: The results showed that, compared to VBRT, APRE can effectively improve the performance of the reactive athletes' lower limb explosive power in the CMJ in a shorter period of time. The findings indicate that APRE may be useful for coaches seeking to improve the CMJ performance of athletes in the short term.

Effect of unilateral training and bilateral training on physical performance: A meta-analysis.

Background: In Unilateral (UNI) exercises are more effective than bilateral (BI) exercises in improving athletic performance is debatable. Objectives: this meta-analysis investigated the effects of UNI and BI exercises on different effect indicators of jump ability, sprint ability, maximal force, change of direction ability, and balance ability. Data Sources: PubMed, Google Scholar, Web of science, CNKI, Proquest, Wan Fang Data. Study Eligibility Criteria: To be eligible for inclusion in the meta-analysis, the study had to be: 1) athletes; 2) UNI training and BI training; 3) the intervention period had to be more than 6 weeks and the intervention frequency had to be more than 2 times/week; 4) the outcome indicators were jumping ability, sprinting ability, maximum strength, and change of direction and balance. Study Appraisal and Synthesis Method: We used the random-effects model for meta-analyses. Effect sizes (standardized mean difference), calculated from measures of horizontally oriented performance, were represented by the standardized mean difference and presented alongside 95% confidence intervals (CI). Results: A total of 28 papers met the inclusion criteria, and Meta-analysis showed that UNI training was more effective than BI training in improving jumping ability (ES = 0.61.0.23 to 0.09; Z = 3.12, p = 0.002 < 0.01), sprinting ability (ES = -0.02, -0.03 to -0.01; Z = 2.73, p = 0.006 < 0.01), maximum strength (ES = 8.95,2.30 to 15.61; Z = 2.64, p = 0.008 > 0.05), change of direction ability (ES = -0.03, -0.06 to 0.00; Z = 1.90, p = 0.06 > 0.01) and balance ability (ES = 1.41,-0.62 to 3.44; Z = 1.36, p = 0.17 > 0.01). The results of the analysis of moderating variables showed that intervention period, intervention frequency and intervention types all had different indicators of effect on exercise performance. Conclusion: UNI training has a more significant effect on jumping and strength quality for unilateral power patterns, and BI training has a more significant effect on jumping and strength quality for bilateral power patterns.

Effects of Velocity-Based versus Percentage-Based Resistance Training on Explosive Neuromuscular Adaptations and Anaerobic Power in Sport-College Female Basketball Players.

The purpose of this study was to compare the impact of velocity-based resistance training (VBRT) and percentage-based resistance training (PBRT) on anaerobic ability, sprint performance, and jumping ability. Eighteen female basketball players from a Sport College were randomly divided into two groups: VBRT (n = 10) and PBRT (n = 8). The six-week intervention consisted of two sessions per week of free-weight back squats with linear periodization from 65% to 95%1RM. In PBRT, the weights lifted were fixed based on 1RM percentage, while in VBRT, the weights were adjusted based on individualized velocity profiles. The T-30m sprint time, relative power of countermovement jump (RP-CMJ), and Wingate test were evaluated. The Wingate test assessed peak power (PP), mean power (MP), fatigue index (FI), maximal velocity (Vmax), and total work (TW). Results showed that VBRT produced a very likely improvement in RP-CMJ, Vmax, PP, and FI (Hedges' g = 0.55, 0.93, 0.68, 0.53, respectively, p < 0.01). On the other hand, PBRT produced a very likely improvement in MP (Hedges' g = 0.38) and TW (Hedges' g = 0.45). Although VBRT showed likely favorable effects in RP-CMJ, PP, and Vmax compared to PBRT (p < 0.05 for interaction effect), PBRT produced greater improvements in MP and TW (p < 0.05 for interaction effect). In conclusion, PBRT may be more effective in maintaining high-power velocity endurance, while VBRT has a greater impact on explosive power adaptations.

Meta-Analysis of the Effects of Plyometric Training on Lower Limb Explosive Strength in Adolescent Athletes.

BACKGROUND: Plyometric training is an effective training method to improve explosive strength. However, the ability to perform plyometric training in the adolescent population is still controversial, with insufficient meta-analyses about plyometric training on lower limb explosive strength in adolescent athletes. OBJECTIVE: To investigate the influence of plyometric training on the explosive strength of lower limbs in adolescent athletes. METHODS: We performed a search of six databases (Web of Science, PubMed, Scopus, ProQuest databases, China National Knowledge Infrastructure (CNKI), and Wan-fang database) from the starting year of inclusion in each database to April 4, 2022. The quality of the included literature was assessed using the Cochrane risk assessment tool, and data were analyzed using the Review Manager 5.4 software. RESULT: Plyometric training had significant effects on the performance of adolescent athletes in countermovement jump (MD = 2.74, 95% CI: 1.62, 3.85, p < 0.01), squat jump (MD = 4.37, 95% CI: 2.85, 5.90, p < 0.01), standing long jump (MD = 6.50, 95% CI: 4.62, 8.38, p < 0.01), 10-m sprint (MD = -0.04, 95% CI: -0.08, -0.00, p = 0.03), and 20-m sprint (MD = -0.12, 95% CI: -0.20, -0.04, p = 0.03); all had positive and statistically significant effects (p < 0.05). CONCLUSION: Plyometric training can significantly enhance the explosive strength of lower limbs in adolescent athletes.

Meta-analysis of the intermittent time of post-activation potentiation enhancement on sprint ability.

INTRODUCTION: In sports, 10 m, 30 m and 40m events are used to test the athlete's acceleration ability, which depends on the coordination of physiological and neural function and can be greatly improved through scientific training. EVIDENCE ACQUISITION: This study conducted a systematic meta-analysis on the intermittent time of post-activation potentiation enhancement (PAPE) and the outcome measure was the sprint ability in 10 m and 30 m events. Data Sources : Web of Science, PubMed, ProQuest, Embase, Science Direct, Google Scholar, WanFang Data and CNKI. Study eligibility criteria : to qualify for inclusion in meta-analysis, the study must be: 1) healthy people (athletes, students); 2) randomized controlled trials; 3) Barbell squat was used to induce PAPE; 4) intervention period of at least 6 weeks; and 5) an outcome indicator of sprinting ability. EVIDENCE SYNTHESIS: We used the inverse-variance random-effects model for meta-analyses. Effect sizes (standardized mean difference), calculated from measures of horizontally orientated performance, were represented by the standardized mean difference and presented alongside 95% confidence intervals (CI). A total of 9 studies including 141 participants, met the inclusion criteria. The sprint ability in 10 meters (ES=-0.03, P<0.0001) and 30 meters events (ES=-0.03, P=0.004) could be significantly improved when the intermittent time of PAPE was 4-8 min. When the intensity of the squat load was 85%1RM~100%1RM, compared with the intermittent time of 0-3min, 9-12min, and more than 13min, the sprint ability in 10 meters (ES=-0.04, P<0.0001) and 30 meters events (ES=-0.08, P=0.0001) was incredibly enhanced if the intermittent time was 4-8 minutes. Compared with college students, the sprint ability in 10-meter (ES=-0.03, P<0.0001) and 30-meter (ES=-0.04, P=0.001) events was significantly improved in athletes when the intermittent time of PAPE was 4-8 minutes. Compared with non-ball games, the sprint ability in 10 meters (ES=-0.04, P<0.0001) and 30 meters (ES=-0.09, P=0.0002) in ball games was significantly improved when the intermittent time of PAPE was 4-8 minutes. CONCLUSIONS: Our meta-analysis indicated that when squats were used as the induction and the load intensity was 85% 1RM~100% 1RM, the sprint ability in 10-meter and 30-meter events could be significantly improved if the intermittent time was 4-8min. According to the analysis on different population, compared with college students and non-ball games, the 10-meter and 30-meter the sprint ability were significantly improved in athletes and ball games when the intermittent time was 4-8 minutes. Therefore, future research should focus on developing a reasonable combination of load stimulation and intermittent time according to the sprint ability to better induce PAPE.

Flywheel eccentric overload exercises versus barbell half squats for basketball players: Which is better for induction of post-activation performance enhancement?

OBJECTIVE: This study compared the post-activation performance enhancement (PAPE) effects of a flywheel eccentric overload (FEOL) exercise and barbell half squats (BHS) on countermovement jump (CMJ) and 30 m sprint performance. METHODS: Twelve male collegiate competitive basketball players were enrolled in this study and they implemented two training protocols: barbell half squat (BHS) and flywheel eccentric overload (FEOL) training. The BHS protocol included three intensities of load: low (40% 1RM), medium (60% 1RM), and high (80% 1RM), with each intensity consisting of 5 sets of 3 repetitions. The FEOL protocol included three inertia intensities: low (0. 015 kg∙m2), medium (0.035 kg∙m2), and high (0.075 kg∙m2), with each intensity consisting of 3 sets of 6 repetitions. The measurement time points were before training (baseline) and at 3, 6, 9, and 12 minutes after training. A two-stage (stage-I and stage-II) randomized crossover design was used to determine the acute effects of both protocols on CMJ and sprint performance. RESULTS: At each training intensity, the jump height, jump peak power output (PPO), jump impulse and 30m sprint speed at 3, 6, 9, and 12 minutes after BHS and FEOL training did not change significantly compared to the baseline. A 2-way ANOVA analysis indicated significant main effects of rest intervals on jump height, jump PPO, and jump impulse, as well as 30m sprint speed. The interaction of the Time × protocol showed a significant effect on jump height between BHS and FEOL groups at high intensity in stage-I (F = 3.809, p = 0.016, df = 4) and stage-II (F = 3.044, p = 0.037, df = 4). And in high training intensity, the jump height at 3 (7.78 ± 9.90% increase, ES = 0.561), 6 (8.96 ± 12.15% increase, ES = 0.579), and 9 min (8.78 ± 11.23% increase, ES = 0.608) were enhanced in I-FEOL group compared with I-BHS group (F = 3.044, p = 0.037, df = 4). In stage-II, the impulse and sprint speed of the FEOL group were significantly higher than those of the BHS group at 6, 9, and 12 min under low (FEOL = 0.015kg∙m2, BHS = 40%1RM), medium(FEOL = 0.035kg∙m2, BHS = 60%1RM), and high (FEOL = 0.075kg∙m2, BHS = 80%1RM) intensities. Furthermore, the sprint speed of the two training protocols did not change at different time points. The interaction of Time × training intensity showed lower sprint speeds in the II-BHS group at a high intensity (BHS = 80%1RM) compared to low (BHS = 40%1RM) and medium (BHS = 60%1RM) training intensities, especially at 9 min and 12 min rest intervals. CONCLUSION: Although barbell half squat training and flywheel eccentric overload training did not provide a significant PAPE effect on explosive power (CMJ and sprint) in male basketball players, FEOL training showed a better potential effect on enhanced CMJ jump performance at the high training intensity.

Comparison of Velocity and Percentage-based Training on Maximal Strength: Meta-analysis.

The purpose was to analyze the comparison of velocity-based resistance training and one-repetition maximum (%1RM) percentage-based training in maximal strength improvement by meta-analyzing and to find the reasons for the controversial findings of different studies. Ten studies were included in the systematic review and seven were subjected to meta-analysis. A total of 139 subjects were selected from the included articles after exclusion, including athletes of different specialties (N=93) and non-athletes mainly from fitness groups (N=46). The overall effect size was SMD=0.26 (95%CL 0.03 to 0.49, P=0.03, I²=0). As for the comparison of the analysis of different intervention objects as subgroups, the effect size of athletes as the subgroup was 0.35 (95%CI 0.06 to 0.64, p=0.02, I²=0), indicating that in the RCT with athletes as the intervention target, the effect of VBRT in improving the maximal strength was significantly different from that of PBT. Velocity-based resistance training might be more effective than percentage-based training in maximal strength improvement, in which velocity-based resistance training is more suitable for athletes in season, while percentage-based training is more suitable for the general sports population. More high-quality researches should deal with the effect of other athletic performance with velocity-based resistance training in the future.

The effects of velocity-based versus percentage-based resistance training on athletic performances in sport-collegiate female basketball players.

Introduction: The study compared the effects of 6-week (2 sessions/week) velocity-based resistance training (VBRT) and percentage-based resistance training (PBRT) on athletic performance in Sport-College female basketball players. Methods: Fifteen participants were assigned to the VBRT (n = 8) or PBRT (n = 7) groups. The load in VBRT group were determined through the sessional target velocity and velocity loss monitoring, whereas PBRT group used a fixed-load based on percentage of 1-repetition maximum (1RM). Both groups completed intervention that involved the free weight back squat and bench press using the same relative load (linear periodization from 65% to 95% 1RM). Training loads data was continuously recorded. Measurements at baseline (T0) and post-training (T2) included 1RM, countermovement-jump (CMJ), squat-jump (SJ), eccentric-utilization-ratio (EUR), drop-jump height and reactive-strength-index (DJ, DJ-RSI), plyometric-push-up (PPU), 505 change-of-direction (COD), 10-m、20-m sprint (T-10、T-20), 17 × 15 m drill-lines (17-drill), Hexagon agility, and functional movement screen (FMS). A mid-term (T1) assessment was included to investigate the short-term effects of both methods and the fluctuation of personalized 1RM. Results: No between-group differences were observed at T0 for descriptive variables (p > 0.05). Both groups showed significant improvement in strength gains for back squat and bench press, but VBRT showed likely to very likely favorable improvements in CMJ, SJ, EUR, DJ-RSI, Hexagon and COD among athletic performance. The VBRT showed likely to very likely improvements in 17-drill and DJ, while PBRT showed unclear effects. The lifted weights adjusted by VBRT method were higher than prescribed by PBRT (p < 0.05) for the same subjects. Conclusion: Compared with fixed-load PBRT, VBRT enhanced power and athletic performance despite similar strength gains. VBRT can be regarded as a more functional resistance-training method under linear periodization.

Effects of sprint interval training on maximal oxygen uptake in athletes: a meta-analysis.

INTRODUCTION: To explore the effects of sprint interval training on maximal oxygen uptake (VO2max) in athletes, and whether exercise mode, number of sprints, sprint duration, and interval duration would positively impact on athletes' VO2max, so as to improve the reference of exercise prescriptions. METHODS: A comprehensive search of the literature was conducted using the key words "sprint interval training" and "maximal oxygen uptake" on databases, including both Chinese and English articles published from the establishment of the database to January 2021. The articles were selected by two independent reviewers. The quality of the included studies was evaluated in compliance with the risk-of-bias assessment tool for randomized controlled trials recommended in the Cochrane Handbook. RESULTS: After screening and exclusion, 12 studies were included in the metaanalysis. VO2max in the sprint training group was significantly increased by 2.23 ml/kg/min (95% CI 0.99-3.48; p = 0.987). Subgroup analysis was conducted on exercise type, number of sprints, sprint duration, interval duration, and training period, the results of which showed that VO2max of sprinting-based group was increased by 2.43 ml/kg/min (95% CI 0.41-4.45; p = 0.987); VO2max of sprint duration group 2.27 ml/kg/min (95% CI 0.83-3.71; p = 0.96); VO2max of interval duration < 3 min group 2.39 ml/kg/min (95% CI 0.74-4.03; p = 0.92); VO2max of 8-12 sprints group 2.57 ml/kg/min (95% CI 0.75-4.38; p = 0.96); VO2max of SIT for 3-4 weeks group 2.78 ml/kg/min (95% CI 1.00-4.57; p = 0.96). The funnel plot and Egger's test did not suggest publication bias. CONCLUSIONS: (1) SIT can significantly enhance VO2max in athletes. (2) The training program of 3-week sprinting-based SIT with 8-12, 20-30s sprints and intervals less than 3 min between each sprint is the most significant in improving VO2max in athletes.