Phototherapy Improves Muscle Recovery and Does Not Impair Repeated Bout Effect in Plyometric Exercise.

ABSTRACT: Padoin, S, Zeffa, AC, Molina Corrêa, JC, de Angelis, TR, Moreira, TB, Barazetti, LK, and de Paula Ramos, S. Phototherapy improves muscle recovery and does not impair repeated bout effect in plyometric exercise. J Strength Cond Res 36(12): 3301-3310, 2022-The effects of photobiomodulation with red (630 nm) and near-infrared (940 nm) light wavelengths were investigated on the inhibition of exercise-induced muscle damage (EIMD) and adaptation to the repeated bout effect (RBE). Twenty-eight healthy men were randomized to receive light-emitting diode therapy (LEDT) at 630 nm (4.6 J·cm -2 , 97 J energy), LEDT at 940 nm (4.6 J·cm -2 , 114 J), or placebo. After LEDT or placebo treatment, subjects performed 100 drop-jumps (5 sets of 20 repetitions). Creatine kinase, delayed-onset muscle soreness (DOMS), countermovement jump (CMJ), and squat jump (SJ) were assessed before, immediately after, and 24, 48, and 72 hours after the bout. After 14 days, the subjects were submitted to the same plyometric exercise, without LEDT, and were evaluated again. Creatine kinase levels increased significantly 72 hours after the first bout in the placebo group in relation to the LEDT 940-nm group ( P < 0.01). The LEDT 630-nm group showed a significant increase in SJ at 24 hours ( P < 0.05), whereas, at 48 hours, the LEDT 940 nm showed a significant increase compared with the placebo group ( P < 0.05). The 2-way analysis of variance revealed an effect for treatment in the SJ ( F = 7.12; P = 0.001). No differences were found between groups for DOMS and CMJ after the first bout. After the second bout of exercise, there was no effect of treatment. The results suggest that treatment with LEDT 630 nm and LEDT 940 nm before eccentric exercise attenuates EIMD without impairing RBE.

Ten Days of Curcumin Supplementation Attenuates Subjective Soreness and Maintains Muscular Power Following Plyometric Exercise.

Curcumin has become a popular product used to decrease inflammation and enhance recovery from exercise. PURPOSE: To determine the effects of curcumin supplementation on delayed onset muscle soreness and muscle power following plyometric exercise. METHODS: Participants (n = 22; five females, 17 males) consumed either curcumin (500 mg) or placebo twice daily for 10 days (6 days pre, day of and 3 days post exercise). Participants completed 5 x 20 drop jumps on day 7. Blood sampling and recovery tests were assessed at pre-supplementation, 24-hours and immediately pre-exercise, and immediately post-, 24, 48 and 72-hours post-exercise. Blood markers included serum creatine kinase (CK) and erythrocyte sedimentation rate (ESR), while soreness was measured during a squat and post vertical jump. RESULTS: Both groups experienced muscle damage post-exercise with elevated CK (403 ± 390 ul; p < 0.01), soreness with squatting (38 ± 29 mm; p < 0.01), and vertical jump (36 ± 30 mm; p < 0.01). Soreness was greater in placebo vs. curcumin 48 h and 72 h post-exercise (p < 0.01); however, CK was not significantly different between groups (p = 0.28) despite being >200 IU·L-1 greater 24 hr post exercise in placebo vs. curcumin. ESR was significantly greater immediately post-exercise (6.3 ± 5.6 vs. 3.4 ± 2.6 mm/hr; p = 0.03), however these were within the normal range for this test and not significantly different between groups (p = 0.25). Vertical jump decreased over time in the placebo, but not curcumin group (19.8 ± 4.8 vs. 21.4 ± 3.2 in; p = 0.01). CONCLUSION: These data suggest curcumin reduces soreness and maintains muscular power following plyometric exercise.

Protective and Recovery Effects of Resveratrol Supplementation on Exercise Performance and Muscle Damage following Acute Plyometric Exercise.

Plyometric exercise (PE) is an effective training method to increase muscle mass and strength. However, excessive or inappropriate conditions might cause exercise-induced muscle damage (EIMD). Resveratrol (RES) is a natural polyphenol plant antitoxin, which improves exercise performance, and exhibits anti-oxidation, anti-inflammatory, and anti-cancer effects. Therefore, this study investigated the effect of RES supplementation on the recovery of muscle damage, inflammation, soreness, muscle power, and anaerobic performance following plyometric-exercise-induced muscle damage (PEIMD). The present study was a double-blind, placebo-controlled research trial. Thirty-six young, untrained males were enrolled into the placebo (n = 12), RES-500 (500 mg RES/day, n = 12), or RES-1000 (1000 mg RES/day, n = 12) group by a jumping height-counterbalanced grouping design. At baseline, to pre-PEIMD, supplements were pre-loaded 7 days before they conducted PEIMD, and the exercise performance, delayed-onset muscle soreness (DOMS) and muscle damage biomarkers were measured over the experimental period at baseline, pre-PEIMD, and post-PEIMD at 2, 24, 48, and 72 h. As a result, we found that, at 72 h post-EIMD, the force peak (FP) and rate of force development (RFD) of the counter movement jump (CMJ) in RES groups showed no significant difference compared to that at baseline but was significantly greater than the placebo group. In the Wingate anaerobic test (WAnT), supplementation in the RES group had a better recovery effect on the relative peak power (RPP), relative mean power (RMP) and fatigue index (FI) (p < 0.05), especially in the high-dose group. For the detection of muscle pain after PEIMD, the RES supplement group was significantly better than the placebo group (p < 0.05). In addition, for muscle damage indexes, such as creatine kinase (CK) and lactate dehydrogenase (LDH), after PEIMD, supplementation with RES could significantly reduce and accelerate recovery (p < 0.05). In addition, the blood biochemical indicators of blood count, liver function, and kidney function showed that RES will not cause adverse risks to the human body. Our results suggest that replenishing RES in advance could effectively reduce muscle pain, increase exercise performance, and decrease muscle damage indicators caused by PEIMD, and the recovery was faster. Therefore, plyometric exercises combined with suitable RES supplementation could be an effective candidate for controlling muscle damage, improving physical adaption, and recovering anaerobic capacity.

Comparison of instability resistance training, traditional resistance training and plyometric training on athletic performance parameters.

OBJECTIVES: The objective of the study was to compare traditional resistance, instability resistance, and plyometric training methods on measures of athletic performance in healthy subjects. METHODS: Sixty five healthy, physically active male students were randomly assigned to the following groups: traditional resistance training (RT, n=22), instability training (IT, n=22), and plyometric training (PLY, n=21).Athletic performance parameters were assessed pre- and post-training using chair squat test, standing stork test, shuttle run test, t-test, and vertical jump test. RESULTS: General linear univariate model with baseline as covariate (ANCOVA) was used for analyzing the change in outcome from baseline to post-treatment. Statistically significant improvement was observed in all the athletic performance parameters in all three groups after seven weeks of training (p-value<0.05). The highest change in chair squat test was reported for RT compared to IT (p-value<0.001) and PLY (p-value<0.001). The change in standing stork test among the IT group was substantially higher than that among RT (p-value=0.007) but did not significantly differ from that among the PLY (p-value=0.27). No statistically significant difference was observed in post-test values of vertical jump test among three groups. The highest change in t-test and shuttle run test was reported for PLY compared to IT (p-value<0.001) and RT (p-value<0.001). CONCLUSIONS: Based on the findings of this study, it is suggested that IT and PLY can be included with traditional RT to improve various aspects of athletic performance in healthy physically active individuals. The current study will give an insight to athletes, coaches, and trainers regarding utilization of appropriate training methods in enhancing athletic performance. However, further research is required to establish the effectiveness.

Validity of judo-specific tests to assess neuromuscular performance of judo athletes.

Uchi-komi Fitness Test (UFT) is a specific judo test that evaluates physiological fitness of judo athletes in similar conditions to judo matches. Neuromuscular parameters obtained by generic and judo-specific tests would aid to get more information about its criterion validity. This study aimed to analyse the relationship between UFT and shoulder external (PTEX) and internal (PTINT) rotation torque, handgrip strength (HGS) and vertical jumps (VJs) performance. The relationship between UFT and Judogi grip strength test (JGST) was also investigated. Eighteen male judo athletes participated in this study. Athletes performed neuromuscular tests (VJ, PTEX, PTINT and HGS) and judo-specific tests (JGST and UFT). Pearson's correlation was used with the level set at p < 0.05. Significant correlation was found between UFT and all VJ variables (r = 0.50-0.72, p < 0.004), UFT a + b (two first series of UFT) and PTEX (r = 0.49, p = 0.033), UFT and PTINT (r = 0.47, p = 0.044). Also, UFT was correlated to JGST (r = 0.50-0.72, p < 0.044, respectively). We conclude that muscle power of lower limbs, PTEX and PTINT was related to UFT. Strength-endurance in the upper limbs (JGST) was also related to the UFT performance.

Short-term branched-chain amino acid supplementation does not enhance vertical jump in professional volleyball players. A double-blind, controlled, randomized study.

INTRODUCTION: To the best of the authors' knowledge, no previous studies have described the effect of branched-chain amino acids (BCAA) on vertical performance during a week in professional volleyball players. This study assessed BCAA supplementation for a week, aiming to improve vertical jump performance in male professional volleyball players. Twelve male volleyballers were randomly assigned to a BCAA group (n = 6) or a control group (n = 6). The BCAA group ingested 21 g over a week, 7 g per day on Monday, Wednesday, and Friday, before a volleyball training session, while the control group drank a placebo drink. Participants performed 8 maximal countermovement jumps (CMJ); the 3 CMJs on Monday and Wednesday were evaluated after warm-up, after plyometric training, and at the end of the training session; and the 2 CMJs on Friday were evaluated after warm-up, and at the end of the training session. Compared with baseline, no significant differences in CMJ over the week were observed in BCAA or control group, neither between groups. The results indicated that 21 g of BCAA supplementation over a week did not improve vertical jump performance in professional volleyball players.

INTRODUCCIÓN: Hasta donde los autores saben, no se han descrito estudios previos sobre el efecto de los aminoácidos ramificados (BCAA) en el rendimiento vertical durante una semana en jugadores de voleibol profesionales. Este artículo estudió la suplementación de BCAA durante una semana con el objeto de mejorar el rendimiento del salto vertical en jugadores de voleibol profesionales masculinos. Doce jugadores de voleibol masculinos se asignaron aleatoriamente a un grupo con BCAA (n = 6) o a un grupo de control (n = 6). El grupo con BCAA ingirió 21 g en una semana, 7 g por día los lunes, miércoles y viernes antes de la sesión de entrenamiento de voleibol, mientras que el grupo de control bebió una bebida placebo. Los participantes realizaron 8 saltos máximos de contramovimiento (CMJ); los 3 CMJ de lunes y miércoles se evaluaron después del calentamiento y del entrenamiento pliométrico, y al final de la sesión de entrenamiento; los 2 CMJ del viernes se evaluaron después del calentamiento y al final de la sesión de entrenamiento. En comparación con el valor inicial, no se observaron diferencias significativas en los CMJ a lo largo de la semana, ni en el grupo BCAA ni en el grupo control, tampoco hubo diferencias entre grupos. Los resultados indicaron que 21 g de BCAA administrados durante una semana no mejoraron el rendimiento del salto vertical en jugadores de voleibol profesionales.

Effect of D-ribose supplementation on delayed onset muscle soreness induced by plyometric exercise in college students.

OBJECTIVE: Previous investigations suggest that appropriate nutritional interventions may reduce delayed onset muscle soreness (DOMS). This study examined the effect of D-ribose supplementation on DOMS induced by plyometric exercise. METHODS: For the purpose of inducing DOMS, 21 untrained male college students performed a lower-limb plyometric exercise session that involved 7 sets of 20 consecutive frog hops with 90-s of rest between each set. Muscle soreness was measured with a visual analogue scale 1-h before, 24-h after, and 48-h after exercise. Subjects were then randomly placed into the D-ribose group (DRIB, n = 11) and the placebo group (PLAC, n = 10) to assure equivalent BMI and muscle soreness. After a 14-d washout/recovery period, subjects performed the same exercise session, with DRIB ingesting a 200 ml solution containing 15 g D-ribose 1-h before, 1-h, 12-h, 24-h, and 36-h after exercise, and PLAC ingesting a calorically equivalent placebo of the same volume and taste containing sorbitol and ß-cyclodextrin. Muscle soreness and isokinetic muscle strength were measured, and venous blood was assessed for markers of muscle damage and oxidative stress 1-h before, 24-h and 48-h after exercise. RESULTS: In DRIB, muscle soreness after 24-h and 48-h in the second exercise session were significantly lower (p < 0.01) than was experienced in the first exercise session. In the second exercise, blood-related markers of muscle soreness, including creatine kinase, lactate dehydrogenase (LDH), myoglobin and malondialdehyde (MDA) in DRIB after 24-h were lower in DRIB after 24-h than in PLAC (MDA, p < 0.05; rest outcomes, p < 0.01). In addition, LDH and MDA in DRIB were significantly lower (p < 0.01) after 24-h in DRIB than in PLAC. No difference was found in isokinetic muscle strength and oxidative stress markers, including superoxide dismutase and total antioxidant capacity, between DRIB and PLAC after 24-h and 48-h. CONCLUSION: D-ribose supplementation reduces muscle soreness, improves recovery of muscle damage, and inhibits the formation of lipid peroxides. Young adult males performing plyometric exercise are likely to realize a DOMS reduction through consumption of D-ribose in 15 g/doses both before (1-h) and after (1-h, 12-h, 24-h, 36-h) exercise. These results suggest that appropriately timed consumption of D-ribose may induce a similar alleviation of exercise-induced DOMS in the general public.

The effect of four weeks of plyometric training on reactive strength index and leg stiffness is sport dependent.

BACKGROUND: Plyometric exercises are often used to develop lower limb strength and performance-related biomechanics such as leg stiffness. However, the effectiveness of plyometric training may depend on participants' own training and performance demands. The purpose of this study was to examine the effect of plyometric training on Reactive Strength Index (RSI) and leg stiffness (Kleg) on young athletes of different sports. METHODS: Forty eight female athletes (25 Taekwondo (TKD) and 23 rhythmic gymnastics (RG), mean±SD: age: 8.94±2.50 years; mass: 29.73±7.69 kg; height: 138.84±11.90 cm; training experience: 4.62±2.37 years) participated in this study. Participants were randomly assigned to experimental (PT, N.=24) and control (CG, N.=24) groups. The PT group followed a twice-weekly plyometric training program for 4 weeks. Plyometric drills lasted approximately 5-10 s, and at least 90 s rest was allowed after each set. To examine RSI, participants performed trials of five maximal CMJs. Submaximal hopping (20 hops) was performed in order to examine leg stiffness. RESULTS: Significant interaction effect was found for RSI and the post hoc analysis showed that RSI significantly increased by 35% (P=0.017) in RG athletes, whereas a significantly reduction by 28% (P=0.004) was revealed in TKD athletes. The interaction effect between time and group was statistically significant for Kleg (P<0.05) with Kleg significantly increasing by 31% (P=0.008) in TKD athletes, but remaining unchanged (P>0.05) in RG athletes. CONCLUSIONS: The results showed that the effect of a 4-week plyometric training program on RSI and leg stiffness is sport dependent. Further, the applied plyometric program was effective in reducing ground contact time and therefore increasing leg stiffness.

Effects of aquatic exercises on postural control and hand function in Multiple Sclerosis: Halliwick versus Aquatic Plyometric Exercises: a randomised trial.

OBJECTIVES: Postural control and hand dexterity are significantly impaired in people with multiple sclerosis (pwMS). Aquatic interventions may have additional benefits in the treatment of pwMS. The purpose of this study is to compare the effects of two different aquatic exercises on postural control and hand function. METHODS: Thirty pwMS, relapsing-remitting type were randomly divided into a Halliwick (Hallw) and an Aquatic Plyometric Exercise (APE) group. The Limits of Stability test was used to evaluate postural control using the Biodex Balance System. The Nine-Hole Peg Test was used to evaluate hand dexterity. Both exercise interventions were performed twice a week for 8 weeks, in a pool with a depth of 120 cm and water temperature of 30-31°C. RESULTS: Limits of stability improved significantly in both groups (p<0.05) and Hallw group completed the test in a significantly shorter time (p<0.05). Hand dexterity improved significantly in both groups (p<0.01). Following intergroup analysis, Hallw group showed significantly higher improvement in hand dexterity and overall limits of stability test score (p<0.05). CONCLUSIONS: This study provides evidence that both Halliwick and APE are effective to treat balance and hand dexterity. This paper is the first evidence on APE for pwMS and showed that it is safe and improved trunk control and hand dexterity.

The effects of tai chi chuan exercise training on countermovement jump performance in the elderly.

This study sought to compare the biomechanical parameters of the lower extremities during a countermovement jump in elderly people who are engaged in frequent practice of tai chi chuan (TCG) and in the general population of healthy elderly people (HG). Each group included 12 participants. Ten Vicon Motion System infrared cameras and two Kistler force plates were employed for measurement. The jump height, duration, centre of mass (COM) displacement, joint ROM, and upward velocity were analysed in this study. Motion analysis and force platform data were combined to calculate joint moments and powers during the takeoff phase. The data were analysed using independent sample t-tests. The results showed that the tai chi chuan practitioner group (0.13 m) achieved 44% higher jump heights (p < 0.05). The COM displacement during squatting was lower in the TCG (0.25 m) than in the HG (0.19 m) (p < 0.05). The knee and ankle ROMs of the TCG were higher than those of the HG (p < 0.05). Peak knee moment 23% and peak knee power 32% higher in TCG compared to the HG (p < 0.05), suggesting that frequent practice of tai chi chuan may slow the rate of knee degeneration.

Effects of Vibration and Non-Vibration Foam Rolling on Recovery after Exercise with Induced Muscle Damage.

We aimed to compare the effects between non-vibration foam rolling (NVFR) and vibration foam rolling (VFR) on visual analogic scale (VAS), pressure pain threshold (PPT), oxygen saturation (SmO2), countermovement jump (CMJ) and hip and knee range of movement (ROM) after eliciting muscle damage through eccentric acute exercise using an inertial flywheel. Thirty-eight healthy volunteers (32 men, 6 women; aged 22.2±3.2 years) were randomly assigned in a counter-balanced fashion to either a VFR or NVFR protocol group. All participants performed a 10x10 (sets x repetitions) eccentric squat protocol to induce muscle damage. The protocols were administered 48-h post-exercise, measuring VAS, PPT, SmO2, CMJ and ROM, before and immediately post-treatment. The treatment technique was repeated on both legs for 1 minute for a total of five sets, with a 30-s rest between sets. The VFR group showed substantially greater improvements (likely to very likely) in the passive VAS (VFR -30.2%, 90% CI -66.2 to -12.8) with chances for lower, similar or greater VAS compared with the NVFR group of 82%, 14% and 4%, respectively and passive extension hip joint ROM (VFR 9.3%, 90% CI 0.2-19.2) with chances for lower, similar or greater ROM compared with the NVFR group of 78%, 21% and 1%, respectively. For intragroup changes, we observed substantial improvements in VAS (p=.05), lateral vastus, rectus femoris and medial vastus PPT. The results suggest that the VFR group achieved greater short-term benefits in pain perception and passive extension hip joint ROM. Both protocols were effective in improving PPT, SmO2, CMJ and knee joint ROM. The enhanced improvement in VAS and hip ROM measures could have significant implications for VFR treatment.

The Effects of Stretching Training on Cardiac Autonomic Function in Obese Postmenopausal Women.

Context • Menopause and obesity are associated with autonomic dysfunction. Unconventional exercise modalities that include an important flexibility component seem to improve cardiac autonomic function by lowering sympathetic tone and increasing vagal modulation of the heart rate (HR). Yet clear evidence of the effects of stretching training (ST) on cardiac autonomic modulation is limited. Objective • The present study intended to examine the effects of ST on HR variability (HRV) and flexibility in obese postmenopausal women. Design • The research team designed a randomized, controlled trial. Setting • The study was conducted at the Florida State University (Tallahassee, FL, USA). Participants • Twenty-four obese, postmenopausal women, aged 50-65 y with a body mass index of >30 but <40 kg/m2 participated in the study. Intervention • Participants were randomly assigned either to an ST group (n = 12) or a no-exercise control group (n = 12). The study was 8 wk in duration. Outcome Measures • Participant HRV and sit-and-reach scores (SRSs) were measured at baseline and after 8 wk of training. Results • Significant decreases occurred for the ST group between baseline and postintervention in sympathetic activity, as measured by normalized low frequency (nLF) power, and in sympathovagal balance, as measured by the ratio of the natural logarithm low frequency (LnLF) activity to the natural logarithm high frequency (LnHF) power, with P < .01 for both measures. The decreases for the ST group were significantly greater than those for the control group for the nLF and LnLF/LnHF, with P < .05 for both measures. Significant increases in vagal tone occurred for the ST group between baseline and postintervention, as measured by the normalized high frequency (nHF) power, with P < .01, and in SRS following ST, with P < .001. The increases for the ST group were significantly greater than those for the control group for the nHF and SRS, with P < .05 for both measures. The changes in SRS were correlated with the changes in the LnLF/LnHF power, with r = .65 and P < .03 negatively correlated. Conclusions • The findings indicated that ST can improve cardiac autonomic modulation by increasing vagal tone and decreasing sympathetic activity in obese postmenopausal women. The improvement in SRS partially explained the decrease in the sympathovagal balance. Because older or obese individuals have a higher risk of developing cardiovascular diseases, they could potentially benefit from ST.

Effects of low-level laser therapy applied before or after plyometric exercise on muscle damage markers: randomized, double-blind, placebo-controlled trial.

Promising effects of phototherapy on markers of exercise-induced muscle damage has been already demonstrated in constant load or isokinetic protocols. However, its effects on more functional situations, such as plyometric exercises, and when is the best moment to apply this treatment (pre- or post-exercise) remain unclear. Therefore, the purpose of this study was to investigate the effect of low-level laser therapy (LLLT) before or after plyometric exercise on quadriceps muscle damage markers. A randomized, double-blinded, placebo-controlled trial was conducted with 24 healthy men, 12 at pre-exercise treatment group and 12 at post-exercise treatment group. Placebo and LLLT (810 nm, 200 mW per diode, 6 J per diode, 240 J per leg) were randomly applied on right/left knee extensor muscles of each volunteer before/after a plyometric exercise protocol. Muscular echo intensity (ultrasonography images), soreness (visual analogue scale - VAS), and strength impairment (maximal voluntary contraction - MVC) were assessed at baseline, 24, 48, and 72 h post-exercise. Legs treated with LLLT before or after exercise presented significantly smaller increments of echo intensity (values up to 1 %) compared to placebo treatments (increased up to ∼7 %). No significant treatment effect was found for VAS and MVC, although a trend toward better results on LLLT legs have been found for VAS (mean values up to 30 % lesser than placebo leg). In conclusion, LLLT applied before or after plyometric exercise reduces the muscle echo intensity response and possibly attenuates the muscle soreness. However, these positive results were not observed on strength impairment.

Branched-chain aminoacid supplementation attenuates a decrease in power-producing ability following acute strength training.

BACKGROUND: This study aimed to investigate the effects of branched-chain amino acid (BCAA) supplementation on recovery of power-producing ability following a strength training (ST) session. METHODS: Eleven resistance-trained males, performed baseline measures of a countermovement jump (CMJ) and a seated shot-put throw (SSPT). In a counterbalanced fashion, participants were provided with either 20-g of BCAA or a placebo. Each dose was divided into two equal quantities and consumed before and after a ST session consisting of various multi-joint barbell exercises. For both conditions, the CMJ and SSPT were repeated at 24-h post-ST, in addition participants attributed their perceived muscle soreness level via a 200-mm visual analogue scale. RESULTS: Following ST there were significant decrements in CMJ (baseline; 55.2±7.4-cm, BCAA; 52.8±5.9-cm placebo; 50.6±7.3-cm) and SSPT (baseline; 4.55±0.56-m, BCAA; 4.37±0.61-m, placebo; 4.22±0.64-m) for both conditions in comparison to baseline values (P<0.05). However, BCAA was shown to attenuate the decrements in CMJ and SSPT performance compared to placebo (P<0.05). Muscle soreness was significantly increased following ST for both conditions, however there were no differences in attributed values following BCAA and placebo ingestion. CONCLUSIONS: BCAA administered acutely before and following intensive ST attenuates a decrease in power-producing ability experienced by resistance-trained males. The apparent small but significant effects on functional power suggest that BCAA is an effective ergogenic aid for athletes who require augmented recovery of power-producing ability following intensive ST.

Effects of plyometric training and creatine supplementation on maximal-intensity exercise and endurance in female soccer players.

OBJECTIVES: To investigate the effects of a six-week plyometric training and creatine supplementation intervention on maximal-intensity and endurance performance in female soccer players during in-season training. DESIGN: Randomized, double-blind, placebo-controlled trial. METHODS: Young (age 22.9±2.5y) female players with similar training load and competitive background were assigned to a plyometric training group receiving placebo (PLACEBO, n=10), a plyometric training group receiving creatine supplementation (CREATINE, n=10) or a control group receiving placebo without following a plyometric program (CONTROL, n=10). Athletes were evaluated for jumping, maximal and repeated sprinting, endurance and change-of-direction speed performance before and after six weeks of training. RESULTS: After intervention the CONTROL group did not change, whereas both plyometric training groups improved jumps (ES=0.25-0.49), sprint (ES=0.35-0.41), repeated sprinting (ES=0.48-0.55), endurance (ES=0.32-0.34) and change-of-direction speed performance (ES=0.46-0.55). However, the CREATINE group improved more in the jumps and repeated sprinting performance tests than the CONTROL and the PLACEBO groups. CONCLUSIONS: Adaptations to plyometric training may be enhanced with creatine supplementation.

Effects of Acute Carnosine and ß-Alanine on Isometric Force and Jumping Performance.

PURPOSE: To assess the effects of acute combined L-carnosine and ß-alanine (Carn-BA) supplementation on isometric and dynamic tasks. METHODS: Twelve healthy participants performed knee-extensor maximal voluntary contractions (MVCs) and countermovement jumps (CMJs) before and after a fatiguing protocol (45-s continuous CMJs). Isometric and dynamic tests were performed 4 h after ingestion of Carn-BA (2 g of L-carnosine and 2 g of ß-alanine) or placebo (PLA), in random order. After the fatiguing protocol, blood lactate concentration ([La-]), general and muscular rating of perceived exertion (RPE), and muscle pain (24 and 48 h after the end of the fatiguing protocol) were assessed. RESULTS: During the fatiguing protocol, significant decreases in jump height and increases in contact time were found in both groups from the 15th second onward to the end of the fatiguing protocol. Average contact time and jump height were respectively lower (-7%; P = .018) and higher (+6%; P = .025) in Carn-BA than in PLA. After the fatiguing protocol, MVC decreased in both PLA and Carn-BA, but it was higher in Carn-BA than in PLA (+15%, P = 0.012), while CMJ did not change. Moreover, general RPE was lower and muscle pain at 24 h was higher in Carn-BA than in PLA, whereas muscle RPE and [La-] did not differ between conditions. CONCLUSIONS: Ingesting Carn-BA before exercise induced positive effects on MVC and CMJ after the fatiguing protocol and improved CMJ performance during the 45-s continuous jumping effort, even when acutely supplemented. Furthermore, Carn-BA reduced the general RPE and increased muscle pain 24 h after the fatiguing task.

Can different conditioning activities and rest intervals affect the acute performance of taekwondo turning kick?

This study compared the acute effect of strength, plyometric, and complex exercises (combined strength and plyometric exercise) in the countermovement jump (CMJ) and frequency speed of kick test (FSKT) and attempted to establish the best rest interval to maximize performance in the CMJ, number of kicks, and impact generated during FSKT. Eleven taekwondo athletes (mean ± SD; age: 20.3 ± 5.2 years; body mass: 71.8 ± 15.3 kg; height: 177 ± 7.2 cm) participated. One control and 9 experimental conditions were randomly applied. Each condition was composed of warm-up, conditioning activity (half-squat: 3 × 1 at 95% 1RM; jumps: 3 × 10 vertical jumps above 40-cm barrier; or complex exercise: half-squat 3 × 2 at 95% 1RM + 4 vertical jumps above 40-cm barrier), followed by different rest intervals (5-, 10-minute, and self-selected) before CMJ and FSKT. The conditions were compared using an analysis of variance with repeated measures, followed by Bonferroni's post hoc test. The alpha level was set at 5%. Significant difference was found in the number of kicks (F9,90 = 1.32; p = 0.239; and η2 = 0.116 [small]). The complex method with a 10-minute rest interval (23 ± 5 repetitions) was superior (p = 0.026) to the control (19 ± 3 repetitions), maximum strength with a self-selected rest interval (328 ± 139 seconds; 18 ± 2 repetitions) (p = 0.015), and plyometric with a 5-minute rest interval (18 ± 3 repetitions) (p < 0.001). Our results indicate that taekwondo athletes increased the number of kicks in a specific test by using the complex method when 10-minute rest interval was used.

ß-Alanine supplementation slightly enhances repeated plyometric performance after high-intensity training in humans.

ß-Alanine (BA) supplementation has become an ergogenic aid amongst competitive athletes to augment intramuscular carnosine content, leading to higher buffer capacity and exercise performance. We investigated 27 regularly trained young males and females who were randomly allocated either to placebo (PL) or BA ingestion for 8 weeks. Every single day, BA or PL (4.0-5.6 g day(-1)) supplements were ingested by participants and associated with a strong plyometric high-intensity training (two sessions per week during the 8 weeks). Before and after training, maximal jump heights were recorded during squat jump (SJ) and countermovement jump (CMJ) and an index of fatigue was recorded as a mean height of 45 consecutive CMJ. Blood lactate was measured at rest, after completing the fatigue test and every 5 min thereafter up to 30 min recovery. After plyometric training, SJ and CMJ were increased, respectively, by 8.8 and 6.4 % in PL group and 9.9 and 11.0 % in BA group (p < 0.01, no difference between groups). Blood lactate reached a maximal value of 9.4 ± 1.6 mmol l(-1) in PL group, and 10.3 ± 1.3 mmol l(-1) in BA group, with a slight better performance in the fatigue test (+8.6 %, p ≤ 0.01) for BA group as compared to PL group. To conclude, 2-month ß-alanine supplementation resulted in a slight improvement of explosive force after 45 maximal consecutive jumps in young athletes. However, the practical adequacy of supplementation remains questionable in an active and healthy population.

Effect of movement velocity during resistance training on neuromuscular performance.

This study aimed to compare the effect on neuromuscular performance of 2 isoinertial resistance training programs that differed only in actual repetition velocity: maximal intended (MaxV) vs. half-maximal (HalfV) concentric velocity. 21 resistance-trained young men were randomly assigned to a MaxV (n=10) or HalfV (n=11) group and trained for 6 weeks using the full squat exercise. A complementary study (n=8) described the acute metabolic and mechanical response to the protocols used. MaxV training resulted in a likely more beneficial effect than HalfV on squat performance: maximum strength (ES: 0.94 vs. 0.54), velocity developed against all (ES: 1.76 vs. 0.88), light (ES: 1.76 vs. 0.75) and heavy (ES: 2.03 vs. 1.64) loads common to pre- and post-tests, and CMJ height (ES: 0.63 vs. 0.15). The effect on 20-m sprint was unclear, however. Both groups attained the greatest improvements in squat performance at their training velocities. Movement velocity seemed to be of greater importance than time under tension for inducing strength adaptations. Slightly higher metabolic stress (blood lactate and ammonia) and CMJ height loss were found for MaxV vs. HalfV, while metabolite levels were low to moderate for both conditions. MaxV may provide a superior stimulus for inducing adaptations directed towards improving athletic performance.

Magnesium status and the physical performance of volleyball players: effects of magnesium supplementation.

The aim of this study was to test the hypothesis that magnesium supplementation influences the physical performance of volleyball players, as the efficacy of this approach remains questionable. Twenty-five professional male volleyball players were assigned randomly to experimental (350 mg Mg · d(-1), 4 weeks) and control groups (500 mg maltodextrin · d(-1), 4 weeks) maintaining inter-group homogeneity of urinary magnesium. Erythrocyte, plasma and urinary magnesium levels, plasma creatine kinase activity, lactate production, maximal oxygen uptake (VO2 max) and plyometric (squat jump, countermovement jump, countermovement jump with arm swing) and isokinetic (peak torque, potency and total work) performances were evaluated before (T0) and after (T1) supplementation. Levels of erythrocyte and urinary magnesium and creatine kinase activity and VO2 max remained within normal ranges in both groups. Plasma magnesium decreased significantly only within the experimental group. Significant decreases in lactate production and significant increases (of up to 3 cm) in countermovement jump and countermovement jump with arm swing values were detected in the experimental group following magnesium supplementation, but not in the control group at T1. It is concluded that magnesium supplementation improved alactic anaerobic metabolism, even though the players were not magnesium-deficient.