Several devices are available to measure vertical jump (VJ) height based on flight time, VJ reach height, or ground reaction forces. The purpose of this study was to determine the accuracy of a VJ mat for measuring flight time and VJ height compared with a VJ tester or a force plate. Seventeen men and 18 women (X ± SD; age = 20.9 ± 0.7 years, height = 176.1 ± 0.9 cm, weight = 72.6 ± 13.5 kg) served as subjects. Subjects performed counter-movement vertical jumps while standing on both a force plate (1,000 Hz) and a VJ mat. A Vertec VJ tester was used to measure jump reach. Compared with the force plate, the VJ mat reported greater VJ height (VJ mat = 0.50 ± 0.12 m, force plate = 0.34 ± 0.10 m) and flight time (VJ mat = 0.629 ± 0.078 seconds, force plate = 0.524 ± 0.077 seconds). Comparison of VJ heights from the VJ mat and the Vertec revealed no significant differences (Vertec = 0.48 ± 0.11 m). Regression analyses indicated strong relationships between testing methods and suggested that high VJ performances may be underestimated with the VJ mat. This particular VJ mat compared favorably with the Vertec but not the force plate. It seems that the different flight times derived from the VJ mat may permit the VJ mat to be in closer agreement with VJ heights from the Vertec. Also, the VJ mat may not be an appropriate tool for assessing high VJ performances (i.e., ≥0.70 m; ≈28 inches). Practitioners and researchers using similar VJ mats may not obtain accurate flight times and may underestimate high performers.

Abstract:Recently, the use of pre-workout supplements has become popular. Research has shown their ability to increase performance for single bouts but little exists showing their ability to maintain this increase in performance over multiple bouts. Purpose: To investigate the effects of supplements on power production and the maintenance of upper and lower body tasks. Methods: Twenty-three males (22.9 ± 3.6 years, 175.6 ± 6.5 cm, 86.9 ± 15.1 kg, 19.1 ± 8.4 BF% mean ± standard deviation (SD)) were familiarized with the testing protocols and maximal bench press performances were attained (109.1 ± 34.0 kg). Utilizing a double-blind crossover design, subjects completed three trials of five countermovement vertical jumps before and after a high-intensity cycle sprint protocol, which consisted of ten maximal 5 s cycle ergometer sprints utilizing 7.5% of the subject's body weight as resistance, with 55 s of recovery between each sprint. Subjects ingested in a randomized order a commercially available pre-workout supplement (SUP), placebo + 300 mg caffeine (CAF), or a placebo (PLA). Peak power (PP), mean power (MP), and minimum power (MNP) were recorded for each sprint. Subjects performed a velocity bench press test utilizing 80% of their predetermined one repetition maximum (1RM) for 10 sets of 3 repetitions for maximal speed, with one-minute rests between sets. Maximal velocity from each set was recorded. For analysis, bike sprint and bench press data were normalized to the placebo trial. Results: Cycle sprint testing showed no significant differences through the testing sessions. In the bench press, the peak velocity was higher with both the SUP and CAF treatments compared to the placebo group (1.09 ± 0.17 SUP, 1.10 ± 0.16 CAF, and 1 ± 0 PLA, p < 0.05) and the supplement group was higher than the PLA for mean velocity (1.11 ± 0.18 SUP and 1 ± 0 PLA, p < 0.05). Vertical jump performance and lactate levels were not significantly different (RMANOVA showed no significant differences from any treatments). Conclusions: Supplementation with a pre-workout supplement or placebo with caffeine showed positive benefits in performance in bench press velocity.

Leucine ingestion reportedly activates the mTOR pathway in skeletal muscle, contributing to a hypertrophy response. The purpose of the study was to compare the post-resistance exercise effects of leucine and whey protein supplementation on endocrine responses and muscle mTOR pathway phosphorylation. On visit 1, subjects (X±SD; n=20; age=27.8±2.8yrs) provided baseline blood samples for analysis of cortisol, glucose and insulin; a muscle biopsy of the vastus lateralis muscle to assess mTOR signaling pathway phosphorylation; and were tested for maximum strength on the leg press and leg extension exercises. For visits 2 and 3, subjects were randomized in a double-blind crossover design to ingest either leucine and whey protein (10g+10g; supplement) or a non-caloric placebo. During these visits, 5 sets of 10 repetitions were performed on both exercises, immediately followed by ingestion of the supplement or placebo. Blood was sampled 30 min post-, and a muscle biopsy 45 min post-exercise. Western blots quantified total and phosphorylated proteins. Insulin increased (α<.05) with supplementation with no change in glucose compared to placebo. Relative phosphorylation of AKT and rpS6 were greater with leucine and whey supplementation compared to placebo. Supplementation of leucine and whey protein immediately after heavy resistance exercise increases anabolic signaling in human skeletal muscle.

Currently there is a lack of research into how women respond to pre-workout supplementation. The effects of supplements on exercise performance in women, specifically to power, must be performed. This study investigated the effects of supplementation on power production and maintenance during a high-intensity cycle ergometry sprint performance, vertical jump performance, and bench press performance in women. It also investigated the effects of supplementation on power production and the maintenance of upper and lower body tasks in women. A total of 23 females (22.9 ± 3.6 years, 175.6 ± 6.5 cm, 86.9 ± 15.1 kg, 19.1 ± 8.4 body fat percentage (BF%) (mean ± std. dev.)) were familiarized with the testing protocol and maximal bench press performances were attained (49.5 ± 15.4 kg). Utilizing a double-blind crossover design, subjects completed three trials of: Five countermovement vertical jumps, a high-intensity cycle sprint protocol, which consisted of 10 maximal, five second cycle ergometer sprints. Subjects performed a velocity bench press test, utilizing 80% of their predetermined one repetition maximum (1RM) for 10 sets of three repetitions for maximal speed. For 20 min prior to each trial, the subjects ingested, in a randomized order, a pre-workout supplement (Supp), placebo+150 mg caffeine (Caff), or a placebo (PL). Peak power (PP), mean power (MP), and minimum power (MNP) were recorded for each sprint. Maximal velocity from each set was also recorded. Bike sprint and bench press data were normalized to the placebo trial for analysis. Blood lactate (bLa − ) was measured immediately prior to each testing session, within 2 min of the completion of the last cycle sprint and following the bench press test. Bike sprint and bench press testing showed no significant differences through the testing sessions, but did significantly decline over test battery (p < 0.05). Vertical jump performance and lactate levels were not significantly different. Supplementation with a pre-workout supplement or placebo with caffeine 20 min prior to participation showed no positive benefits to performance in female participants.

This study examined the kinetic contributions of the upper extremities during counter-movement vertical jumps (CMVJ) while using arm swing (AS) or no-arm swing (NAS) conditions. Fourteen healthy men (X¯±SD; age = 24.1±3.9 yrs) volunteered for this investigation. Subjects performed in random order a total of 6 jumps consisting of 3 AS and 3 NAS CMVJ. A motion capture system was used to analyze the kinetic data. Paired samples t-tests were used to examine the subjects' mean differences in the AS and NAS CMVJ trials (p<0.05). Results for all subjects were determined for each jump performed, with statistical analyses performed on mean values for all three jumps per subject. The AS significantly increased the vertical jump height (VJH) by an average of 0.07±0.03 m (3.0±1.3 in). DXA scans determined the upper limbs were 12.0% of the total body mass. Movement of the upper limbs during the AS CMVJ produced 32.2±7.0% of the total mean ground reaction force (GRF), and 11.3±2.2% during the NAS CMVJ. The enhancement of performance when jumping using an AS resulted in a 13.6% increase in VJH. The contribution of the upper limbs during the AS CMVJ averaged 31.5% of the peak GRF which occurred immediately before takeoff. The upper extremities can greatly influence vertical jump performances and the accompanying kinetics. When analyzing jump GRFs, one must be aware of how much the upper limbs contribute to these forces. Additionally, proper arm swing mechanics must be emphasized when instructing correct jump technique.