Post-activation potentiation effect of eccentric overload and traditional weightlifting exercise on jumping and sprinting performance in male athletes

The impact of post-activation potentiation on explosive vertical jump after intermittent time: a meta-analysis and systematic review

The optimal intermittent time for post-activation potentiation (PAP) training remains uncertain and contentious. This study employed a meta-analysis to systematically evaluate the effect of different intermittent times on PAP in relation to explosive vertical jump height. Relevant literature was sourced from CNKI, Wanfang, VIP, CBM, PubMed, Web of Science, and Google Scholar databases using keywords such as "postactivation potentiation," "activation enhancement effect," "PAP," "explosive vertical jump," "explosive vertical high jump," and "intermittent time." The search covered publications from the inception of each database until June 2024. Studies involving athletes (regardless of sport type) undergoing PAP training were included, with no restrictions on the methods used to induce PAP. Comparative analysis focused on the heights of countermovement jumps (CMJ) and peak ground reaction force (GRF) before and after interventions. The quality of the included studies was assessed using the Cochrane Risk of Bias Tool, and data were analyzed using RevMan5.3. The study included a total of 21 papers with 327 subjects, primarily using the squat as the method of PAP induction. The meta-analysis revealed that intermittent times of 4 min [MD = - 0.03, 95% CI: - 0.04 ~ - 0.01; Z = 2.71, P = 0.007] and 5-8 min [MD = - 0.03, 95% CI: - 0.04 ~ - 0.01; Z = 3.07, P = 0.002] significantly increased the height of explosive vertical CMJs. However, intermittent times of 1-3 min [MD = -0.00, 95% CI: - 0.01 ~ 0.01; Z = 0.38, P = 0.70] and 10-24 min [MD = - 0.01, 95% CI: - 0.02 ~ 0.00; Z = 1.43, P = 0.15] did not show significant effects on CMJ height. These findings indicate that 4-min and 5-8 min intervals significantly enhance CMJ height, while intervals shorter than 4 min or longer than 8 min do not have a significant impact.

Carbohydrate Mouth Rinses before Exercise Improve Performance of Romanian Deadlift Exercise: A Randomized Crossover Study

(1) Background: This study compared the effects of mouth rinsing with a carbohydrate trial (CMR) and a placebo trial (PL) on concentric and eccentric contraction strength in multi-joint resistance exercise performance. (2) Methods: Twenty healthy adult men (age: 22.4 ± 3.7 years, body mass index: 26 ± 3.8, peak power: 378.3 ± 138.7 W) were recruited in this study. Participants were employed in a double-blind, randomized crossover design to divide participants into carbohydrate mouth rinsing trial (CMR) and placebo trial (PL). After warming up, participants used 6.6% maltodextrin (CMR) or mineral water (PL) to rinse their mouth for 20 s. Next, the participants underwent tests of maximum inertial Romanian deadlift resistance exercise comprising five sets of six reps, with 3 min rests between sets. After deducting the first repetition of each set, the mean values from the five sets were analyzed. (3) Results: The concentric peak power of the CMR trial was significantly higher than that of the PL trial (p = 0.001, Cohen's d = 0.46), the eccentric peak power of the CMR trial was significantly higher than that of the PL trial (p = 0.008, Cohen's d = 0.56), and the total work of the CMR trial was significantly higher than that of PL trial (p = 0.002, Cohen's d = 0.51). (4) Conclusions: These findings demonstrate that mouth rinsing with carbohydrates before exercise can improve concentric and eccentric contraction strength in multi-joint resistance exercise performance.

Dose-Response Effect of an Inertia Flywheel Postactivation Performance Enhancement Protocol on Countermovement Jump Performance

The purpose of this study was to investigate the dose-response effect of a high-load, 6-repetition, maximum effort inertial flywheel (IFw) squat postactivation performance enhancement (PAPE) protocol on countermovement jump (CMJ) performance metrics. Thirteen subjects completed 5 squat testing sessions: 1 session to determine back-squat 6-repetition maximum, 1 session to determine 6-repetition maximum IFw load, and 3 sessions to investigate the dose-response effect of an IFw PAPE protocol set at the load determined in the second session. In the IFw PAPE sessions, subjects completed either 1, 2, or 3 sets of IFw squats, then performed 5 CMJs over 12 minutes (1, 3, 6, 9, and 12 min post-IFw). All CMJ tests were conducted on a force platform where CMJ performance outcomes and impulse variables were calculated. There was no main time or volume effect for jump height, contact time, reactive strength index, peak force, or any of the impulse variables. A main time effect was identified for flight time (P = .006, effect size = 0.24) and peak power (P = .001, effect size = 0.28). The lack of change in jump height may indicate that too much fatigue was generated following this near-maximal IFw squat protocol, thereby reducing the PAPE effect.

The effect of flywheel complex training with eccentric-overload on muscular adaptation in elite female volleyball players

This study aimed to compare the effects of 8 weeks (24 sessions) between flywheel complex training with eccentric overload and traditional complex training of well-trained volleyball players on muscle adaptation, including hypertrophy, strength, and power variables. Fourteen athletes were recruited and randomly divided into the flywheel complex training with an eccentric-overload group (FCTEO, n = 7) and the control group (the traditional complex training group, TCT, n = 7). Participants performed half-squats using a flywheel device or Smith machine and drop jumps, with three sets of eight repetitions and three sets of 12 repetitions, respectively. The variables assessed included the muscle thickness at the proximal, mid, and distal sections of the quadriceps femoris, maximal half-squats strength (1RM-SS), squat jump (SJ), countermovement jump (CMJ), and three-step approach jump (AJ). In addition, a two-way repeated ANOVA analysis was used to find differences between the two groups and between the two testing times (pre-test vs. post-test). The indicators of the FCTEO group showed a significantly better improvement (p < 0.05) in CMJ (height: ES = 0.648, peak power: ES = 0.750), AJ (height: ES = 0.537, peak power: ES = 0.441), 1RM-SS (ES = 0.671) compared to the TCT group and the muscle thicknes at the mid of the quadriceps femoris (ES = 0.504) after FCTEO training. Since volleyball requires lower limb strength and explosive effort during repeated jumps and spiking, these results suggest that FCTEO affects muscular adaptation in a way that improves performance in well-trained female volleyball players.

Does the sequence of plyometric and dynamic stretching exercises influence subsequent sprint performance? A randomized crossover intervention study

The objectives of this study were to evaluate the acute effects of the sequence order of drop jumps (DJ) and dynamic stretching (DS) on sprinting performances in competitive athletes and to investigate the relationships between post-activation performance enhancement (PAPE) in sprint performance and lower limb power. Thirteen male jumpers and sprinters participated in this study (19 ± 2 years; 177 ± 7 cm; 71.7 ± 5.6 kg). Through a randomized crossover design, the athletes were exposed to three different conditions after a standardized warm-up: DS+DJ, DJ+DS, and control. Sprinting performance over 40 m was analysed with consideration of initial (0 to 20 m) and final acceleration (20 to 40 m) phases. The effect of intervention was examined by two-way repeated-measures of ANOVA. Pearson's correlation test was used to determine the association between PAPE during sprinting and jump performance. There was no effect of any factor on 40-m sprint performance. Meanwhile, the performance at 20-40 m was higher after the DS+DJ condition when compared to baseline (8.79 ± 0.43 vs. 8.91 ± 0.35 m/s; p = 0.015). However, the initial acceleration was worsened in the DJ+DS condition when compared to baseline (6.26 ± 0.25 vs. 6.22 ± 0.26 m/s; p = 0.002). There was a negative correlation between CMJ height and the improvement in final acceleration (r = -0.741; p = 0.004). The use of DS prior to DJ is an effective strategy to improve performance in the final acceleration phase (20-40 m). The athletes with lower levels of lower limb power benefited the most from this PAPE strategy.

Current Guidelines for the Implementation of Flywheel Resistance Training Technology in Sports: A Consensus Statement

BACKGROUND

Flywheel resistance training has become more integrated within resistance training programs in a variety of sports due to the neuromuscular, strength, and task-specific enhancements reported with this training.

OBJECTIVE

This paper aimed to present the consensus reached by internationally recognized experts during a meeting on current definitions and guidelines for the implementation of flywheel resistance training technology in sports.

METHODS

Nineteen experts from different countries took part in the consensus process; 16 of them were present at the consensus meeting (18 May 2023) while three submitted their recommendations by e-mail. Prior to the meeting, evidence summaries were developed relating to areas of priority. This paper discusses the available evidence and consensus process from which recommendations were made regarding the appropriate use of flywheel resistance training technology in sports. The process to gain consensus had five steps: (1) performing a systematic review of systematic reviews, (2) updating the most recent umbrella review published on this topic, (3) first round discussion among a sample of the research group included in this consensus statement, (4) selection of research group members-process of the consensus meeting and formulation of the recommendations, and (5) the consensus process. The systematic analysis of the literature was performed to select the most up-to-date review papers available on the topic, which resulted in nine articles; their methodological quality was assessed according to AMSTAR 2 (Assessing the Methodological Quality of Systematic Review 2) and GRADE (Grading Recommendations Assessment Development and Evaluation). Statements and recommendations scoring 7-9 were considered appropriate.

RESULTS

The recommendations were based on the evidence summary and researchers' expertise; the consensus statement included three statements and seven recommendations for the use of flywheel resistance training technology. These statements and recommendations were anonymously voted on and qualitatively analyzed. The three statements reported a score ranging from 8.1 to 8.8, and therefore, all statements included in this consensus were considered appropriate. The recommendations (1-7) had a score ranging from 7.7 to 8.6, and therefore, all recommendations were considered appropriate.

CONCLUSIONS

Because of the consensus achieved among the experts in this project, it is suggested that practitioners and researchers should adopt the guidelines reported in this consensus statement regarding the use of flywheel resistance technology in sports.

The Effect of Post-Activation Potentiation Enhancement Alone or in Combination with Caffeine on Anaerobic Performance in Boxers: A Double-Blind, Randomized Crossover Study

Post-activation performance enhancement (PAPE) is a physiological phenomenon that refers to an acute excitation of the neuromuscular system following intense exercise that ends in enhanced physical performance in a subsequent bout of exercise. The scientific literature has primarily examined the effectiveness of PAPE alone or combined with caffeine (CAF) intake in all-out tests lasting ≤10 s, as the effect of PAPE is transitory. The aim of the present study was to determine the effect of a protocol to induce PAPE alone or in combination with caffeine intake on the 30 s Wingate Anaerobic Test in highly trained boxers. Twenty-five male and highly trained boxers (mean age: 20 ± 1 years) participated in a double-blind, randomized crossover study consisting of three different experimental conditions: (i) control (CON), with no substance intake and no PAPE protocol before the Wingate Anaerobic Test; (ii) PAPE + PLA, involving the intake of a placebo 60 min before and a PAPE protocol comprising a 10 s cycling sprint overloaded with 8.5% of the participants' body weight 10 min before the Wingate Anaerobic Test; and (iii) PAPE + CAF, involving the intake of 3 mg/kg of caffeine 60 min before and the same PAPE protocol used in the (ii) protocol before the Wingate Anaerobic Test. In all conditions, the participants performed the 30 s version of the Wingate Anaerobic Test with a load equivalent to 7.5% of their body weight, while the cycle ergometer setting was replicated. Immediately following the Wingate test, heart rate (HR), the rating of perceived exertion (RPE), and blood lactate concentration (Bla) were measured. In comparison to CON, PAPE + PLA enhanced mean power (p = 0.024; Effect size [ES] = 0.37) and total work (p = 0.022; ES = 0.38) during the Wingate test, accompanied by an increase in post-test blood lactate concentration (p < 0.01; ES = 0.83). In comparison to CON, PAPE + CAF enhanced mean power (p = 0.001; ES = 0.57), peak power (p = 0.013; ES = 0.57), total work (p = 0.001; ES = 0.53), post-test blood lactate concentration (p < 0.001; ES = 1.43) and participants' subjective perception of power (p = 0.041). There were no differences in any variable between PAPE + PLA and PAPE + CAF. In summary, a PAPE protocol that involves a 10 s all-out sprint 10 min before the Wingate Anaerobic Test was effective in enhancing Wingate mean power in highly trained boxers. The addition of 3 mg/kg of caffeine to the PAPE protocol produced an effect on mean power of a higher magnitude than PAPE alone, and it enhanced peak power along with participants' subjective perception of power. From a practical point of view, PAPE before exercise seems to be an effective approach for increasing Wingate performance in highly trained boxers, while the addition of caffeine can increase some benefits, especially peak power.

Acute Effects of Different Conditioning Activities on Amateur Soccer Players

Several warm-up activities are used to prepare soccer players for training and games. However, few studies have focused on comparing different activities (strength vs. stretching) in young and amateur athletes, especially for performance improvement in explosive actions. Thus, in order to compare the effect of four conditioning activities on jump and sprint performances, 12 soccer athletes (age: 19±0.8; weight (kg): 72.8±8.0; height (cm): 180±6.7) performed four warm-up activities: strength exercise (cluster system), combined exercise, plyometric exercise, and static stretching (control). The countermovement jump (CMJ) and 30-meter run (30-m Sprint) were performed 10 min after each experimental condition. A ONE-WAY ANOVA test of repeated measures was conducted with a Tukey's post-hoc test to compare the conditions. The strength conditioning activity protocol (33.68±2.87) showed a significant difference for the CMJ from static stretching (30.96±3.16) (p>0.05). There were significant differences regarding the 30-m Sprint test between strength conditioning (4.72±0.19) and combined activities (4.71±0.21) compared to static stretching (4.84±0.21) (p>0.05). In conclusion, the combined conditioning activity and strength protocols can be chosen in warm-up activities instead of static stretching (control condition) for improved immediate sprint and jump abilities in amateur soccer players.

Post flywheel squat vs. flywheel deadlift potentiation of lower limb isokinetic peak torques in male athletes

The present study investigated the post-activation performance enhancement (PAPE) of isokinetic quadriceps and hamstrings torque after flywheel (FW)-squat vs. FW-deadlift in comparison to a control condition. Fifteen male athletes were enrolled in this randomised, crossover study. Each protocol consisted of 3 sets of 6 repetitions, with an inertial load of 0.029 kg.m2. Isokinetic quadriceps (knee extension) and hamstrings (knee flexion) concentric peak torque (60º/s) and hamstring eccentric peak torque (-60º/s) were measured 5 min after experimental or control conditions. A significant condition (PAPE) effect was reported (f = 4.067, p = 0.008) for isokinetic hamstrings eccentric peak torque following FW-squat and FW-deadlift, but no significant differences were found for quadriceps and hamstrings concentric peak torques. The significant difference averaged 14 Nm between FW-squat vs. control (95% CI: 2, 28; d = 0.75, moderate; p = 0.033), and 13 Nm between FW-deadlift vs. control (95% CI: 1, 25; d = 0.68, moderate; p = 0.038). This study reported that both FW-squat and FW-deadlift exercises are equivalently capable of generating PAPE of isokinetic hamstrings eccentric torque. Practitioners may use these findings to inform strength and power development during complex training sessions consisting of flywheel-based exercises prior to a sport-specific task.

Postactivation Potentiation for Muay Thai Kicking Performance

ABSTRACT

Brown, L, Doyle, G, Bruce-Low, S, Domingos, S, Anthony, K, Rowan, F, and Galbraith, A. Postactivation potentiation for Muay Thai kicking performance. J Strength Cond Res 37(10): 2032-2037, 2023-The purpose of this study was to investigate the effects of postactivation potentiation (PAP) on Muay Thai kicking performance based on 3 different rest intervals. Aiming to quantify and indicate timing protocols for conditioning coaches when training athletes using PAP. 17 male (25.3 ± 3.6 years old; 179.3 ± 2.3 cm; 78.0 ± 5.2 kg), experienced Muay Thai fighters completed a standardized warm-up, including a 10-minute cycle on the Wattbike at 60 watts and 30 body mass squats for a dynamic stretch. Subjects then completed a baseline test by striking a PowerKube using the roundhouse and Teep kick techniques. PAP exercise consisted of 4 squat repetitions to maximum effort, followed by a rest period of 2, 5, or 8 minutes. Subjects then struck the PowerKube again using the roundhouse and Teep kick techniques. Rest periods were presented in a randomized order on separate days, with 72 hours between conditions. The level of significance was set at α = 0.05. Significant increases in both roundhouse (χ 2 (3) = 38.51, p < 0.05) and Teep kick (χ 2 (3) = 26.33, p < 0.05) striking power were observed when compared with baseline. For the roundhouse kick, significant differences and large effect sizes were present between all conditions except baseline and 2-minute rest. For the Teep kick, significant differences and large effect sizes were present between baseline and 5-minute rest and baseline and 8-minute rest. This indicates that PAP with 5- or 8-minute rest increased roundhouse and Teep kick power. This research reports that a PAP stimulus from a 4RM squat exercise, followed by a 5- or 8-minute rest period, enhances kick power in trained Muay Thai fighters. This technique provides a readily available, time-efficient method to enhance performance that can be built into the warm-up procedure of athletes before training or competition.

Using Deadlifts as a Postactivation Performance Enhancement Strategy in Warm-ups in Football

ABSTRACT

Abade, E, Brito, J, Gonçalves, B, Saura, L, Coutinho, D, and Sampaio, J. Using deadlifts as a postactivation performance enhancement strategy in warm-ups in football. J Strength Cond Res 37(9): 1821-1827, 2023-Postactivation performance enhancement activities may be relevant warm-up strategies aiming to improve subsequent physical performance. The purpose of the current study was to investigate the effects of adding barbell deadlift or hex-bar deadlift exercises to current warm-up routines on running and jumping performances in football players. Ten highly trained male football players participated in the study during the competitive phase of the season. All players performed 3 protocols in the same week: a standard warm-up that included players' regular routines and 2 other protocols with the addition of barbell or hex-bar deadlift, after the end of the warm-up (3 sets of 3 reps, progressing set by set from 60% to 85% repetition maximum). All protocols had the same time interval between pretest (immediately after the warm-up) and posttest (15 minutes after the warm-up). Vertical jumping (countermovement jump [CMJ]; Abalakov jump [AJ]) and running performances (505 test) were impaired 15 minutes after the standard warm-up (CMJ: -6.7 ± 4.2%; AJ: -8.1 ± 8.4%; and 505 time: 1.4 ± 2.5%). For warm-up with the addition of barbell deadlift, vertical jump increased by 4.3 ± 5.6% (Cohen's dunb : 0.23 [0.02-0.47]) and 505 time decreased by -5.9 ± 3.6% (Cohen's dunb : 0.97 [-1.68 to -0.43]). The warm-up with hex-bar deadlift led to trivial changes for CMJ and AJ, but 505 time decrease by -2.7 ± 2.6% (Cohen's dunb : -0.53 [-1.01 to -0.13]). The deadlift exercise can be added to warm-up routines to maintain or even enhance acute physical performance. However, coaches and practitioners should be aware that performance enhancements resultant from deadlift may vary according to individual physical profiles.

Post-activation performance enhancement of flywheel training on lower limb explosive power performance

The study aimed to investigate the post-activation performance enhancement (PAPE) of flywheel training (FT) on lower limb explosive power performance. Using a randomized crossover design, 20 trained men (age = 21.5 ± 1.4 years; training experience 5.5 ± 1.2 years) completed seven main conditions after three familiarization sessions. The first three conditions tested the PAPE of the FT on the counter movement jump (CMJ) under three different inertial loads (0.041 kg·m2 as L; 0.057 kg·m2 as ML; and 0.122 kg·m2 as P), whereas the following four conditions tested the PAPE of FT on the 30 m sprint, which consisted of three inertial loads (L, ML, and P) and a control condition. Participants were required to perform the CMJ or 30 m sprint at baseline (Tb) and immediately (T0), 4 min (T4), 8 min (T8), 12 min (T12), and 16 min (T16) after exercise, respectively. The results of the CMJ conditions showed that PAPE peaked at T4 (p < 0.01) and almost subsided at T12 (p > 0.05) in ML and P conditions. Meanwhile, PAPE appeared earlier in the P condition, and the effect was more significant (P:ES = 1.09; ML:ES = 0.79). 30 m sprint results showed significant improvement only in the ML condition. The PAPE peaked at T4 (p < 0.05, ES = -0.47) and almost subsided at T8 (p > 0.05). It was mainly due to the significant enhancement of the 10-30 m segmental timing performance at T4 (p < 0.05, ES = -0.49). This study indicates that the size of the inertial load could influence the magnitude of the PAPE produced by the explosive force of the lower limb. The PAPE of the vertical explosive force increased with increasing inertial load, but the PAPE of the horizontal explosive force did not appear at the maximum inertial load. The most effective elicitation of the PAPE was at 4-8 min after the FT.

Building for the Future: A Systematic Review of the Effects of Eccentric Resistance Training on Measures of Physical Performance in Youth Athletes

BACKGROUND

Eccentric resistance training is recognised as an effective stimulus for enhancing measures of muscular strength and power in adult populations; however, its value in youth athletes is currently not well understood.

OBJECTIVE

The aim of this systematic review was to critically appraise the effects of eccentric resistance training on measures of physical performance (i.e. muscular strength, jump, sprint and change of direction) in youth athletes 18 years of age and under.

METHODS

Original journal articles published between 1950 and June 2022 were retrieved from electronic search engines of PubMed, SPORTDiscus and Google Scholar's advanced search option. Full journal articles investigating the acute and chronic effects of eccentric resistance training on measures of physical performance in youth athletes (i.e. a person 18 years of age or under who competes in sport) were included. The methodological quality and bias of each study were assessed prior to data extraction using a modified Downs and Black checklist.

RESULTS

The search yielded 749 studies, of which 436 were duplicates. Three-hundred studies were excluded based upon title and abstract review and a further 5 studies were removed following the modified Downs and Black checklist. An additional 14 studies were identified during backward screening. Accordingly, 22 studies were included in our systematic review. The Nordic hamstring exercise and flywheel inertial training were the most frequently used eccentric resistance training methods in youth athletes. Improvements in physical performance following the Nordic hamstring exercise are dependent upon an increase in the breakpoint angle, rather than training volume (sets and repetitions), and are further elevated with the addition of hip extension exercises or high-speed running. A minimum of 3 familiarisation trials is necessary to elicit meaningful adaptations following flywheel inertial training. Furthermore, an emphasis should be placed upon decelerating the rotating flywheel during the final one to two thirds of the eccentric phase, rather than gradually throughout the entire eccentric phase.

CONCLUSIONS

The findings of this systematic review support the inclusion of eccentric resistance training in youth athletes to improve measures of muscular strength, jump, sprint and change of direction performance. The current eccentric resistance training methods are predominantly limited to the Nordic hamstring exercise and flywheel inertial training; however, the efficacy of accentuated eccentric loading to improve jump performance warrants attention in future investigations.

Post-Activation Performance Enhancement and Motor Imagery Are Efficient to Emphasize the Effects of a Standardized Warm-Up on Sprint-Running Performances

Warm-up routines include various tasks focused on the peripheral contractile properties and nervous motor command. This present study was aimed at investigating the acute effects of different warm-up routines, emphasizing either peripheral (post-activation performance enhancement, PAPE) or central (motor imagery, MI) contributions on sport-specific tasks. Eleven young female athletes took part in this cross-over, randomized, controlled trial. They underwent three experimental sessions composed of a standardized warm-up followed by 10 min of (1) rest (CONTROL), (2) maximal concentric leg press (PAPE), or (3) mental repetitions of sprint tasks (MI). Post-tests consisted of reaction time, arrowhead agility test, 20 m sprint, repeated sprint ability, and NASA-TLX fatigue questionnaire. PAPE and MI significantly enhanced the arrowhead agility test (p < 0.001 and p = 0.012, respectively) and repeated sprint ability (p = 0.002 and p = 0.035, respectively) compared to CONTROL, without any difference between PAPE and MI. The 20 m sprint time was better after PAPE as compared to MI (p = 0.005) and CONTROL (p < 0.001), without any difference between MI and CONTROL. Reaction time and the NASA-TLX questionnaire were not affected by the warm-up modalities (p > 0.05). PAPE was the most efficient to optimize warm-up due to its greater peripheral contribution that would improve muscle contractility. MI specifically improved the imagined tasks mostly by central contribution.

Estimating the Standing Long Jump Length from Smartphone Inertial Sensors through Machine Learning Algorithms

The length of the standing long jump (SLJ) is widely recognized as an indicator of developmental motor competence or sports conditional performance. This work aims at defining a methodology to allow athletes/coaches to easily measure it using the inertial measurement units embedded on a smartphone. A sample group of 114 trained young participants was recruited and asked to perform the instrumented SLJ task. A set of features was identified based on biomechanical knowledge, then Lasso regression allowed the identification of a subset of predictors of the SLJ length that was used as input of different optimized machine learning architectures. Results obtained from the use of the proposed configuration allow an estimate of the SLJ length with a Gaussian Process Regression model with a RMSE of 0.122 m in the test phase, Kendall's τ < 0.1. The proposed models give homoscedastic results, meaning that the error of the models does not depend on the estimated quantity. This study proved the feasibility of using low-cost smartphone sensors to provide an automatic and objective estimate of SLJ performance in ecological settings.

Modified Isoinertial-Based Ruffier Test in Healthy Individuals: A Feasibility Study

Cardiorespiratory fitness is an essential indicator in sports science and sports medicine that can be assessed with several tests. The Ruffier test is a submaximal test valid to estimate maximum oxygen uptake; it consists of 30 squats in 45 s, which may be challenging for inexperienced individuals. This study aims to verify the feasibility of a modified inertial-based version of the Ruffier test to assess cardiorespiratory fitness with 10 squats in 15 s. Both classic and isoinertial Ruffier tests were administered to thirty-five healthy young adults (20 men and 15 women), age 22.06 ± 2.13 years, BMI 23.87 ± 2.74. The two one-sided test confirmed the comparability of the isoinertial Ruffier test with its classic version within equivalence bounds of ±3.726. Furthermore, gender, age, body weight, the difference between peak heart rate after isoinertial squatting and resting heart rate, and the isoinertial Ruffier index are the coefficients of our best VO₂max prediction model with an adjusted R² of 0.937, sensitivity of 0.89, and specificity of 0.81. The study evidenced the feasibility of the isoinertial Ruffier test to measure cardiorespiratory fitness through a quick, safe, and short squat test easy to perform in fitness centers and primary care clinics.

Validity and Reliability of Inertial Measurement System for Linear Movement Velocity in Flywheel Squat Exercise

The aim of this study was to examine the validity and reliability of an Inertial Measurement System integrated into a secondary pulley (IMS) for determining linear velocity during flywheel squat exercises. Thirty-one male participants who were highly experienced in a flywheel resistance exercise training performed flywheel squat exercises with three incremental loads, and mean velocity (MV), mean propulsive velocity (MPV) and max velocity (Vmax) of the exercises were simultaneously recorded with a validated linear encoder and the IMS, in two different sessions. Validity was analyzed using ordinary least products regression (OLP), Lin's concordance correlation coefficient (CCC), and Hedge's g for the values from the linear encoder and the IMS. Test-retest reliability was determined by coefficient of variation (CV), Intraclass correlation coefficient (ICC), and standard error of measurement (SEM). Results showed a high degree of validity (OLP intercept = -0.09-0.00, OLP slope = 0.95-1.04, CCC = 0.96-0.99, Hedge's g < 0.192, SEM = 0.04-0.08) and reliability (CV < 0.21%, ICC > 0.88, SEM < 0.08). These results confirm that the IMS provides valid and reliable measures of movement velocity during flywheel squat exercises.

Eccentric resistance training with neurological conditions: A meta analysis

BACKGROUND

People with neurological conditions are exposed to muscle wasting resulting in reduced strength and endurance. Both deficiencies negatively impact gait and balance, each of which can be benefited by strengthening exercises. Unfortunately, people with neurological conditions often do not have the ability to perform traditional weight training as their endurance and strength fail to meet the minimum threshold for improvement. An alternative to traditional, full range of motion lifting is eccentric resistance training (ERT).

RESEARCH QUESTION

The current systematic review and meta-analysis sought to evaluate the efficacy of ERT against conventional therapeutic modalities or weightlifting on walking speed, Timed Up and Go (TUG), and maximum voluntary isometric contraction (MVIC) in individuals with neurological conditions.

METHODS

Web of Science, PubMed, and Academic Search Complete were searched until September 1, 2020, followed by a manual search on December 3, 2021. Publications were included if they were peer reviewed, available in English, consisted of a pre-specified neurological disorder, involved human subjects, had an eccentric and "traditional" therapy; and reported at least one of the outcome measures at both pre- and post-intervention.

RESULTS

Thirteen studies of human subjects (n = 297) and 47 standardized mean differences (SMD) were included in the multilevel model analysis. The analysis revealed a small, albeit non-significant effect on performance (TUG, MVIC, walking speed) when comparing traditional therapies and ERT (SMD: 0.136; 96; 95 % CI: -0.0002, 0.050).

SIGNIFICANCE

There appears to be no difference between ERT and traditional therapy or weightlifting on measured outcomes. In this way, ERT is as effective as traditional therapeutics and full range of motion weightlifting to improve movement in clinical populations. Practitioners working with populations with neurological conditions may consider supplementing or replacing traditional strengthening activities with ERT as clients can complete greater volumes of work with lower metabolic demand.

Time Duration of Post-Activation Performance Enhancement (PAPE) in Elite Male Sprinters with Different Strength Levels

(1) Purpose: This study aimed to explore the time duration of post-activation performance enhancement (PAPE) in elite male sprinters with different strength levels. (2) Methods: Thirteen elite male sprinters were divided into a strong group (relative strength: 1RM squat normalized by body mass of ≥2.5; n = 6) and a weak group (relative strength of <2.5; n = 7). All sprinters performed one static squat jump (SSJ) at baseline and 15 s, 3 min, 6 min, 9 min, and 12 min following an exercise protocol including three reps of a 90% 1RM back squat. Two force plates were used to determine the vertical jump height, the impulse output, and the power output for all SSJs. (3) Results: Significant improvements in vertical jump height and peak impulse were observed (p < 0.05) at 3, 6, and 9 min, without significant between-group differences. The peak power had a significant increase in 3 min (p < 0.01) and 6 min (p < 0.05), with also no significant difference between-group differences. Moreover, the stronger subjects induced a greater PAPE effect than the weaker counterparts at 3, 6, and 9 min after the intervention. The maximal benefit following the intervention occurred at 6 min and 3 min after the intervention in the stronger and weaker subjects, respectively. (4) Conclusions: The findings indicated that three reps of a 90% 1RM back squat augmented the subsequent explosive movement (SSJ) for 3−9 min in elite male sprinters, especially in stronger sprinters.

Motoric performance variation from morning to evening: 80% intensity post-activation potentiation protocol impacts performance and its diurnal amplitude in basketball players

Introduction

Post-activation potentiation (PAP) can be defined as the acute enhancement in muscle performance after preload stimulation that occurs during strength exercises or warm-up protocols, and the contractile history of any muscle group can directly influence the presented performance. The purpose of this study was to compare the results of motoric performance tests carried out at two different times of the day using three different PAP protocols.

Methods

Thirty-two male basketball players with at least 2 years of training experience and who competed at the national level were recruited for this study [age: 21.80 ± 1.91 years; body height: 178.40 ± 6.85 cm; body mass: 72.50 ± 7.16 kg; body mass index (BMI): 22.81 ± 2.28]. After control and experimental-specific warm-up (SWU) sessions, participants completed a countermovement jump (CMJ) and seated medicine ball throw (SMBT). The SWU protocol was developed based on the athlete's typical warm-up routine. The experimental warm-ups included the same exercises as the SWU, with one set of bench presses for five repetitions at 80% (80% PAP) and one repetition at 100% of 1 RM (100% PAP). Each of the protocols consists of 15 min. The SWU and experimental warm-up sessions were completed in a random, counterbalanced order, completed in a period of 3-weeks.

Results

According to the research findings, carrying out the protocols in the evening led to a larger improvement in SMBT than in the morning (F = 35.94, p < 0.001, η ² _p = 0.537). Additionally, the SMBT results were statistically more significant in the group that received 80% PAP compared to the SWU (p = 0.034), and the SMBT results were also higher in the group that received 100% PAP compared to the SWU (p = 0.002). Furthermore, the interaction effect (time × PAP) was statistically significant in SMBT (F = 6.39, p = 0.003, η ² _p = 0.17).

Discussion

These results may provide more particular recommendations than previously thought to basketball coaches for the planning of basketball-specific PAP exercises prior to the start of training programs.

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.

Acute Effects of Post‑Activation Performance Enhancement of 5RM Weighted Pull‑Ups and One Arm Pull‑Ups on Specific Upper Body Climbing Performance

This study aimed to compare the acute effects of performing two kinds of pull-ups: traditional, pronated grip pull-ups performed with two arms and additional weight with loading intensity of 5RM and one-arm pull-ups, on specific upper body climbing power. Twenty-four advanced climbers participated in the study. The International Rock Climbing Research Association (IRCRA) Power Slap Test was chosen to assess specific upper body climbing power. All athletes performed the test under three conditions: control (without a conditioning activity) and both kinds of pull-ups as conditioning activities. Results revealed significant improvements in the Power Slap's distance, power, velocity, and force in 5RM weighted pull-ups, but not in one-arm pull-ups. In the latter case, participants reached higher power values after the conditioning stimulus, but the effect size was small. Also, the differences with the remaining variables (power, speed, and force) were non-significant. The results suggest that weighted pull-ups with a 5RM intensity and not one arm pull-ups seem to be an effective PAPE stimulus. Therefore, the former can be used as a conditioning activity before an explosive climbing exercise such as the Power Slap on a campus board.

Appropriate Reporting of Exercise Variables in Resistance Training Protocols: Much more than Load and Number of Repetitions

Manipulating resistance training variables is crucial to plan the induced stimuli correctly. When reporting the exercise variables in resistance training protocols, sports scientists and practitioners often refer to the load lifted and the total number of repetitions. The present conceptual review explores all within-exercise variables that may influence the strength and hypertrophic gains, and the changes in muscle architecture. Together with the (1) load and (2) the number of repetitions, (3) performing repetitions to failure or not to failure, (4) the displacement of the load or the range of movement (full or partial), (5) the portion of the partial movement to identify the muscle length at which the exercise is performed, (6) the total time under tension, the duration of each phase and the position of the two isometric phases, (7) whether the concentric, eccentric or concentric-eccentric phase is performed, (8) the use of internal or external focus and (9) the inter-set rest may all have repercussions on the adaptations induced by each resistance exercise. Manipulating one or more variable allows to increase, equalize or decrease the stimuli related to each exercise. Sports scientists and practitioners are invited to list all aforementioned variables for each exercise when reporting resistance training protocols.

The impact of resistance exercise range of motion on the magnitude of upper-body post-activation performance enhancement

Background

Various studies have used different exercise protocols as post-activation performance enhancement (PAPE) stimulus; however, little attention has been given to the effects of exercise range of motion on the PAPE effect and subsequent performance enhancement. This study aimed to compare the PAPE responses induced by the bench press performed with different ranges of motion on subsequent bench press throw performance.

Methods

Ten resistance-trained males (age: 26 ± 3 years; body mass: 93.2 ± 9.4 kg; height: 181 ± 6 cm; experience in resistance training: 6.3 ± 2.4 years; relative bench press one-repetition maximum (1RM) 1.54 ± 0.2 kg/body mass) performed four experimental sessions consisting of a single set of the bench press at 80%1RM until mean barbell velocity dropped by 10% as the conditioning activity (CA) with a (1) standard, (2) cambered, (3) and reversed cambered barbell or a control condition in which the participants did not perform any CA. To assess the PAPE effect, single-sets of 2 repetitions of the bench press throw at 30%1RM were performed before and after the CA at the following time points: 2, 4, 6, 8, 10 min.

Results

The two-way ANOVA (4 conditions × 2time points) showed a significant interaction for peak power (p < 0.001; η² = 0.556) and peak velocity (p = 0.001; η² = 0.457). The standard barbell bench press CA led to the greatest performance enhancement in peak power (p = 0.001; ES = 0.54) and in peak velocity (p = 0.002; ES = 0.71) within the examined conditions.

Conclusions

The results of this study indicate that the range of motion of the CA has a significant impact on the magnitude of the PAPE response, and the greatest effect can be reached when the range of motion of the CA and the subsequent explosive task is similar.

The Effect of Flywheel Inertia on Peak Power and Its Inter-session Reliability During Two Unilateral Hamstring Exercises: Leg Curl and Hip Extension

This study investigated the effect of flywheel moment of inertia (0.029, 0.061, and 0.089 kg·m2) on concentric and eccentric peak power and eccentric:concentric peak power ratio during unilateral flywheel leg curl and hip extension exercises. Moreover, the inter-session reliability of peak power was analyzed during both exercises. Twenty amateur male soccer athletes attended five visits-performing three sets of eight repetitions of either unilateral leg curl or hip extension (all three moments of inertias) during each visit. For the unilateral leg curl, there were no differences in any measure between moments of inertia (p = 0.479) but a higher eccentric than concentric peak power for all moments of inertia (p < 0.001). For the unilateral hip extension, differences between moments of inertia were reported for all measures (p < 0.05). Specifically, the lowest moment of inertia elicited the greatest concentric peak power (p = 0.022), there were no differences with the medium inertia (p = 0.391), and the greatest moment of inertia obtained the greatest eccentric peak power (p = 0.036). Peak power measures obtained acceptable to excellent reliability while the eccentric:concentric ratio reported unacceptable to good reliability for both exercises. A variety of moments of inertia can elicit high eccentric knee flexor demands during unilateral leg curls, whereas higher moments of inertia are needed to achieve an eccentric-overload in peak power during hip extensions. Different exercises may have different inertia-power relationships. Concentric and eccentric peak power measures should continue to inform training, while the eccentric:concentric ratio should not be used.

The effect of flywheel training on strength and physical capacities in sporting and healthy populations: An umbrella review

The aim of this umbrella review was to provide a detailed summary of how flywheel training enhances strength and physical capacities in healthy and athletic populations. The eleven reviews included were analyzed for methodological quality according to the Assessing the Methodological Quality of Systematic Review 2 (AMSTAR 2) and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. Two were systematic reviews, six were systematic reviews with meta-analyses and three were narrative reviews. Although the included reviews support use of flywheel training with athletic and healthy populations, the umbrella review highlights disparity in methodological quality and over-reporting of studies (38 studies were included overall). Flywheel post-activation performance enhancement protocols can effectively enhance strength and physical capacities acutely with athletes and healthy populations. All relevant reviews support flywheel training as a valid alternative to traditional resistance training for enhancing muscular strength, power, and jump performance with untrained and trained populations alike. Similarly, reviews included report flywheel training enhances change of direction performance—although conclusions are based on a limited number of investigations. However, the reviews investigating the effect of flywheel training on sprint performance highlight some inconsistency in attained improvements with elite athletes (e.g., soccer players). To optimize training outcomes, it is recommended practitioners individualize (i.e., create inertia-power or inertia-velocity profiles) and periodize flywheel training using the latest guidelines. This umbrella review provides an analysis of the literature’s strengths and limitations, creating a clear scope for future investigations.

Post-activation Performance Enhancement after a Bout of Accentuated Eccentric Loading in Collegiate Male Volleyball Players

The purpose of this study was to investigate the benefit of post-activation performance enhancement (PAPE) after accentuated eccentric loading (AEL) compared to traditional resistance loading (TR). Sixteen male volleyball athletes were divided in AEL and TR group. AEL group performed 3 sets of 4 repetitions (eccentric: 105% of concentric 1RM, concentric: 80% of concentric 1RM) of half squat, and TR group performed 3 sets of 5 repetitions (eccentric & concentric: 85% of 1RM). Countermovement jump (CMJ), spike jump (SPJ), isometric mid-thigh pull (IMTP), and muscle soreness test were administered before (Pre) exercise, and 10 min (10-min), 24 h (24-h), and 48 h (48-h) after exercise. A two-way repeated measures analysis of variance was used to analyze the data. Peak force and rate of development (RFD) of IMTP in AEL group were significantly greater (p < 0.05) than TR group. The height, peak velocity, and RFD of CMJ, height of SPJ, and muscle soreness showed no interaction effects (p > 0.05) groups x time. AEL seemed capable to maintain force production in IMTP, but not in CMJ and SPJ. It is recommended the use of accentuated eccentric loading protocols to overcome the fatigue.

The Maximum Flywheel Load: A Novel Index to Monitor Loading Intensity of Flywheel Devices

BACKGROUND

The main aim of this study was (1) to find an index to monitor the loading intensity of flywheel resistance training, and (2) to study the differences in the relative intensity workload spectrum between the FW-load and ISO-load.

METHODS

twenty-one males participated in the study. Subjects executed an incremental loading test in the squat exercise using a Smith machine (ISO-load) or a flywheel device (FW-load). We studied different association models between speed, power, acceleration, and force, and each moment of inertia was used to find an index for FW-load. In addition, we tested the differences between relative workloads among load conditions using a two-way repeated-measures test.

RESULTS

the highest r2 was observed using a logarithmic fitting model between the mean angular acceleration and moment of inertia. The intersection with the x-axis resulted in an index (maximum flywheel load, MFL) that represents a theoretical individual maximal load that can be used. The ISO-load showed greater speed, acceleration, and power outcomes at any relative workload (%MFL vs. % maximum repetition). However, from 45% of the relative workload, FW-load showed higher vertical forces.

CONCLUSIONS

MFL can be easily computed using a logarithmic model between the mean angular acceleration and moment of inertia to characterize the maximum theoretical loading intensity in the flywheel squat.

Weightlifting for Children and Adolescents: A Narrative Review

The involvement of youth in the sport of weightlifting and the use of weightlifting methods as part of training for youth sport performance appears to be increasing. Weightlifting for children and adolescents has been criticized in some circles and is a controversial aspect of resistance training for young people. Although injuries can occur during weightlifting and related activities, the incidence and rate of injury appear to be relatively low and severe injury is uncommon. A number of performance, physical, and physiological variables, such as body composition, strength, and power, are improved by weightlifting training in children, adolescents, and young athletes. Manipulating program variables, when appropriate, can have a substantial and profound influence on the psychological, physiological, physical, and performance aspects of weightlifters. An understanding of the sport, scientific training principles, and musculoskeletal growth development is necessary to properly construct a reasonable and appropriate training program. A scientific background aids in providing an evidenced basis and sound rationale in selecting appropriate methods and directing adaptations toward more specific goals and enables the coach to make choices about training and competition that might not otherwise be possible. If weightlifting training and competition are age group appropriate and are properly supervised, the sport can be substantially safe and efficacious.

The impact of foot angle on lower limb muscles activity during the back squat and counter movement jump

BACKGROUND

Squatting is a core exercise for many purposes. However, there is still controversy surrounding the practice of targeting specific muscle groups when performing the back squat with different stance widths or foot positions. Therefore, this study aimed to assess lower limb muscle activation during different form of back squat when adopting three different foot angles.

METHODS

Eight male active participants (age 24.0±0.8 years, height 1.80±0.63m and mass 85.8±8.7kg) performed maximal isometric squat, back squat with an overalod of 80% of 1 repetition maximum, and countermovement jump (CMJ) when adopting three foot rotation angles: parallel (0°); +10° outward (external rotation); +20° outward (external rotation). We calculated the root mean square of the electromyographic signals recorded from eight participant's dominant leg muscles.

RESULTS

During the descending phase of the back squat, the 20° external foot rotation elicited greater activation of the biceps femoris (+35%; p = 0.027) and gastrocnemius medialis (+70%; p = 0.040) compared to parallel foot. There were no significant differences among the other muscles and exercise conditions.

CONCLUSIONS

The +20° foot position increased BF and GasM muscle activity only during the downward phase of the back squat. Strength coaches should consider the present findings when selecting specific resistance exercises aiming to improve athletes' strength and physical fitness.

Utilisation of Post-Activation Performance Enhancement in Elderly Adults

With age, many physiological changes occur in the human body, leading to a decline in biological functions, and those related to the locomotor system are some of the most visible. Hence, there is a particular need to provide simple and safe exercises for the comprehensive development of physical fitness among elderly adults. The latest recommendations for the elderly suggest that the main goal of training should be to increase muscle power. The post-activation performance enhancement effect underpinning complex training might be an approach that will allow for the development of both muscle strength and velocity of movement, which will result in an increase in muscle power and improve the ability to perform daily activities and decrease injury risk. This article briefly introduces a complex training model adapted to the elderly with its potential benefits and proposes a direction for further studies.

Order of concentric and eccentric muscle actions affects metabolic responses

BACKGROUND

Resistance exercise provides an effective stimulus for improving the metabolic plasticity of skeletal muscle, and the type of acute muscle contraction plays an important role in determining specific responses and adaptations. The purpose of the current investigation was to examine the effect of contraction order on metabolic responses by comparing monophasic concentric and eccentric squats versus a protocol incorporating alternated concentric and eccentric repetitions.

METHODS

Twelve recreationally active men (21.1±1.1yr) performed three nearly identical squat protocols on separate days. Protocols varied only with contraction-type, including 4 sets × 10 reps concentric-only (CON), eccentric-only (ECC), and BOTH which alternated 5 concentric followed by 5 eccentric reps (CON-ECC; sets 1 and 3) and vice versa (ECC-CON; sets 2 and 4). The experimental trials were performed once weekly in a randomized, counter-balanced order, and expired gases were collected using a two-way non-rebreathing mask and oxygen consumption quantified with indirect calorimetry. Subjects raised (CON) and lowered (ECC) the load in 2s, and all sets (2 min) and repetitions (8 s) were separated by standardized rest intervals.

RESULTS

From the BOTH protocol, the increase in metabolic rate was significantly greater (P≤0.05) during squats performed with CON-ECC order (0.60±0.11 L·min^-1) compared to ECC-CON (0.44±0.07 L·min^-1), but excess postexercise oxygen consumption (EPOC) was opposite, with significantly greater metabolic rate during the 2-minute rest intervals after ECC-CON squats (0.46±0.09 L·min^-1) compared to CON-ECC (0.25±0.05 L·min^-1). Metabolic rates during and after squats were significantly greater (P≤0.05) with CON (0.63±0.09; 0.49±0.10 L·min-1) compared to ECC (0.34±0.04; 0.20±0.04 L·min-1), respectively.

CONCLUSIONS

These data present an interesting paradigm regarding the contraction-dependent metabolic responses to monophasic resistance exercise and suggest a greater EPOC following concentric versus eccentric muscle actions.

Effects of flywheel training on strength-related variables in female populations. A systematic review

This study aimed to evaluate the effect of flywheel training on female populations, report practical recommendations for practitioners based on the currently available evidence, underline the limitations of current literature, and establish future research directions. Studies were searched through the electronic databases (PubMed, SPORTDiscus, and Web of Science) following the preferred reporting items for systematic reviews and meta-analysis statement guidelines. The methodological quality of the seven studies included in this review ranged from 10 to 19 points (good to excellent), with an average score of 14-points (good). These studies were carried out between 2004 and 2019 and comprised a total of 100 female participants. The training duration ranged from 5 weeks to 24 weeks, with volume ranging from 1 to 4 sets and 7 to 12 repetitions, and frequency ranged from 1 to 3 times a week. The contemporary literature suggests that flywheel training is a safe and time-effective strategy to enhance physical outcomes with young and elderly females. With this information, practitioners may be inclined to prescribe flywheel training as an effective countermeasure for injuries or falls and as potent stimulus for physical enhancement.

Post Flywheel Squat Potentiation of Vertical and Horizontal Ground Reaction Force Parameters during Jumps and Changes of Direction

(1) Background: The aim of the study was to determine the post-activation performance enhancement (PAPE) of vertical and horizontal ground reaction force parameters during jumps and change of direction following flywheel squat exercise using two different flywheel inertias. (2) Methods: Eleven male athletes performed a countermovement jump (CMJ), standing broad jump (SBJ), and “modified 505” change of direction (COD) in a control condition and 6 minutes following three sets of six repetitions of flywheel half squats at one of two inertias (0.029 kg·m² and 0.061 kg·m²). Peak directional ground reaction force, power, and rate of force development were calculated for each test. (3) Results: Higher inertia flywheel squats were able to acutely enhance CMJ peak vertical force (Bayes Factor (BF₁₀) = 33.5, very strong; δ = 1.66; CI: 0.67, 2.70), whereas lower inertia flywheel squats were able to acutely enhance CMJ peak vertical power (BF₁₀ = 3.65, moderate; δ = 0.93; CI: 0.11, 1.88). The vertical squat exercise induced no PAPE effect on resultant SBJ or horizontal COD ground reaction force parameters, nor were any differences observed between the inertias. (4) Conclusions: Researchers and practitioners should consider the kinetic and kinematic correspondence of a pre-load stimulus to the subsequent sport-specific activity (i.e., flywheel squat to CMJ).

Post-activation performance enhancement (PAPE) after a single bout of high-intensity flywheel resistance training

This study investigated the post-activation performance enhancements (PAPE) induced by a high-intensity single set of accentuated eccentric isoinertial resistance exercise on vertical jump performance. Twenty physically active male university students performed, in randomized counterbalanced order, two different conditioning activities (CA) after a general preestablished warm-up: a conditioning set of 6 maximum repetitions at high intensity (i.e., individualized optimal moment of inertia [0.083 ± 0.03 kg·m^-2]) of the flywheel half-squat exercise in the experimental condition, or a set of 6 maximal countermovement jumps (CMJ) instead of the flywheel exercise in the control condition. CMJ height, CMJ concentric peak power and CMJ concentric peak velocity were assessed at baseline (i.e., 3 minutes after the warm-up) and 4, 8, 12, 16 and 20 minutes after the CA in both experimental and control protocols. Only after the experimental protocol were significant gains in vertical jump performance (p < 0.05, ES range 0.10–1.34) at 4, 8, 12, 16 and 20 minutes after the CA observed. In fact, the experimental protocol showed greater (p < 0.05) CMJ height, concentric peak power and concentric peak velocity enhancements compared to the control condition. In conclusion, a single set of high-intensity flywheel training led to PAPE in CMJ performance after 4, 8, 12, 16 and 20 minutes in physically active young men.

Concentric and eccentric inertia-velocity and inertia-power relationships in the flywheel squat

The aim of this study was to evaluate the effects of varying flywheel inertia on velocity and power during flywheel squats. Fifteen healthy physically active males performed 6 maximal effort flywheel half-squats at each of 0.029, 0.061, 0.089 and 0.121 kg·m², with velocity recorded via 3D motion capture and power recorded via inbuilt transducer. Peak concentric velocity (χ2 = 37.9; p < 0.001), peak eccentric velocity (χ2 = 24.9; p < 0.001), mean concentric velocity (F(3) = 52.7; p < 0.001) and mean eccentric velocity (χ2 = 16.8; p < 0.001) all tended to decrease with increases in flywheel inertia, whereas the ratio of peak eccentric to peak concentric power (F(3) = 4.26; p = 0.010) tended to increase. Flywheel inertia had no significant effect on peak concentric or eccentric power, or the ratio of eccentric to concentric peak or mean velocities. The best fit subject-specific inertia-velocity relationships were reported for peak concentric velocity (median linear R² = 0.95, median logarithmic R² = 0.97). The results suggest that velocity, rather than power, should be used to prescribe and monitor flywheel squat exercise intensities, and that individualized linear relationships between inertia and peak concentric velocity can be used for this purpose.

Influence of Strength Level on the Acute Post-Activation Performance Enhancement Following Flywheel and Free Weight Resistance Training

This study aimed to compare the post-activation potentiation performance enhancement (PAPE) response to the acute inertial flywheel (FW) and free weight resistance training (TRA) on subsequent countermovement jump (CMJ) and sprint performance (10 m sprint). This study used a randomized crossover design including twenty-eight healthy males that were divided into strong (relative one-repetition maximum (1RM) back squat > 2.0 × body mass) and weak (relative 1RM back squat < 2.0 × body mass) groups. All participants performed the following: (a) three reps at 90% of their 1RM back squat (TRA) and (b) three reps on an inertial FW (plus one repetition to initiate flywheel movement) with an intensity that generated a mean propulsive velocity equal to that achieved with 90% of the 1RM back squat. Before and after the conditioning activity, participants performed two CMJs and two 10 m sprints. Within-group analyses showed significantly greater CMJ (d > 0.9, p < 0.001) and sprint performance (d > 0.5, p < 0.05) in the FW and the TRA group. Between-group analysis showed that sprint changes were significantly greater in the FW-strong group when compared with the TRA (F_1,18 = 5.11, p = 0.036, η²_p = 0.221-large) group. These results suggest that using a squat activation protocol on a FW may lead to an acute positive effect on jump and sprint performance, especially in stronger individuals.

Postactivation potentiation effects of Back Squat and Barbell Hip Thrust exercise on vertical jump and sprinting performance

BACKGROUND

This study aimed to determine and compare the post-activation potentiation (PAP) effects of the Back Squat (SQ-PAP) and Hip Thrust (HT-PAP) exercises in terms of vertical jump height (VJ), 20-yard dash and 40-yard dash time in physically active university students. Considering the Force-vector theory, it was hypothesized that HT-PAP would induce greater potentiation for 40-yard dash than SQ-PAP whereas SQ-PAP would induce greater potentiation for 20-yard dash and VJ than HT-PAP.

METHODS

Seventeen kinesiology and exercise science students (8 male and 9 female) who resistance train at least 3 times/week (age, 21.71±1.49 years; body mass, 75.58±11.89 kg; height, 173.98±11.88 cm and training experience 5.47±2.00 years) joined this study. They performed three experimental sessions namely; baseline (BL), SQ-PAP loading session and HT-PAP loading session with 48 hours interval with a randomized open crossover study design. BL session was also accepted as control and familiarization session. SQ-PAP and HT-PAP exercises were performed roughly at 90% of 1 Repetition maximum (1 RM) of the subjects with three repetitions. Subjects were tested for vertical jump height (VJ), 20-yard dash and 40-yard dash time before and 8 minutes after each PAP loading exercise.

RESULTS

Statistical analysis revealed that the potentiation effects of SQ-PAP and HT-PAP exercises on VJ height, 20-yard and 40-yard dash were similar that none of the loading exercises with 8 min rest interval had any increasing or detrimental performance effect on VJ (P=0.923), 20-yard dash (P=0.133) as well 40-yard dash time (P=0.570).

CONCLUSIONS

These findings demonstrate that none of the loading protocols with above mentioned exercises have any detrimental or improving effects on VJ height, 20-yard dash and 40-yard dash time for physically active university students who joined this study. Although no acute potentiation effect has been found, this study also shows that SQ-PAP, HT-PAP exercises can be used interchangeably and safely to avoid training monotony during longer training periods for chronic adaptations.