Effects of Load on Peak Power Output Fatigue During the Bench Throw.

Boffey, D, Sokmen, B, Sollanek, K, Boda, W, and Winter, S. Effects of load on peak power output fatigue during the bench throw. J Strength Cond Res 33(2): 355-359, 2019-The ability to create power is an important variable for athletic success. No study to date has compared peak power output (PPO) fatigue across multiple sets and with different loads with the bench throw. This study aimed to begin the process of establishing empirical upper-body power training guidelines for moderately strong athletes by determining how load (30, 45, and 60% 1 repetition maximum [1RM]) affects PPO (Watts) dropoff during 3 sets of 10 repetitions of the bench throw. Ten resistance-trained male volunteers ([mean ± SD]: age 20.58 ± 1.36 years, height 176.05 ± 9.09 cm, body mass 78.65 ± 9.93 kg, bench press 1RM 99.79 ± 18.52 kg) performed 3 sets of 10 repetitions of the bench throw with one of the 3 loads during 3 weekly sessions. A Humac 360 device collected concentric phase PPO data during each repetition. The data were analyzed using one-way (treatment) and 2-way (treatment × time) repeated-measures analysis of variance. A significant decrease in PPO was observed during repetitions 5-7 at 30%, 3-4 at 45%, and 2-3 at 60% 1RM. Based on the results of this study, coaches who want to maximize power should potentially keep sets of upper-body plyometrics within these repetition ranges. The authors recommend that moderately strong athletes perform the bench throw on a Smith machine at 45% or 60% 1RM to produce high PPO over multiple sets.

Effects of Sprint Interval Training With Active Recovery vs. Endurance Training on Aerobic and Anaerobic Power, Muscular Strength, and Sprint Ability.

Sökmen, B, Witchey, RL, Adams, GM, and Beam, WC. Effects of sprint interval training with active recovery vs. endurance training on aerobic and anaerobic power, muscular strength, and sprint ability. J Strength Cond Res 32(3): 624-631, 2018-This study compared sprint interval training with active recovery (SITAR) to moderate-intensity endurance training (ET) in aerobic and anaerobic power, muscular strength, and sprint time results. Forty-two recreationally active adults were randomly assigned to a SITAR or ET group. Both groups trained 3× per week for 10 weeks at 75% of V[Combining Dot Above]O2max for 30 minutes weeks 1-4, with duration increasing to 35 minutes weeks 5-7 and 40 minutes weeks 8-10. While ET ran on a 400-m track without rest for the full training session, SITAR sprinted until the 200-m mark and recovered with fast walking or light jogging the second 200 m to the finish line in 3× original sprint time. Maximal oxygen consumption (V[Combining Dot Above]O2max), anaerobic treadmill run to exhaustion at 12.5 km·h at 20% incline, isokinetic leg extension and flexion strength at 60 and 300°·s, and 50 m sprint time were determined before and after training. Results showed a significant improvement (p ≤ 0.05) in absolute and relative V[Combining Dot Above]O2max, anaerobic treadmill run, and sprint time in both groups. Only SITAR showed significant improvements in isokinetic leg extension and flexion at 300°·s and decreases in body mass (p ≤ 0.05). SITAR also showed significantly greater improvement (p ≤ 0.05) over ET in anaerobic treadmill run and 50 m sprint time. These data suggest that SITAR is a time-efficient strategy to induce rapid adaptations in V[Combining Dot Above]O2max comparable to ET with added improvements in anaerobic power, isokinetic strength, and sprint time not observed with ET.

Repetitive box lifting performance is impaired in a hot environment: implications for altered work-rest cycles.

This study investigated the effects of environmental temperature on repetitive box lifting (RBL) performance, associated stress hormone and creatine kinase (CK) responses. Ten healthy males performed two experimental trials in a random crossover design. The trials consisted of three 40 min (10 min sitting, 20 min standing, and 10 min RBL) circuits performed in either 23 °C or 38 °C followed by a 180 min seated recovery period in 23 °C. RBL performance (i.e., number of boxes lifted) was reduced (p ≤ 0.05) in 38 °C compared to the 23 °C trial. Physiological Strain Index was significantly different between trials (38 °C: 8.5 ± 1.1 versus 23 °C: 7.2 ± 0.7; p ≤ 0.01). Plasma testosterone was elevated (p ≤ 0.05) across both trials and then decreased at 60 min recovery, compared to pre-exercise (PRE) measures, but was higher (p ≤ 0.05) during the 38 °C trial. Plasma cortisol increased (p ≤ 0.05) at 60 min during both trials and remained elevated until 120 min in 23 °C, and until 60 min recovery in 38 °C. Serum CK was greater through 48 hr post compared to PRE values in both trials. Thus, 10 min RBL performance was reduced in 38 °C despite the 30-min rest periods between RBL intervals. Plasma testosterone and cortisol were generally higher during the 38 °C trial, suggesting a greater stress response. Additional research is needed to determine optimal work:rest cycles for maximizing work performance in thermally oppressive environments.

Effects of Panax notoginseng (Chinese ginseng) and acute exercise on postprandial glycemia in non-diabetic adults.

The purpose of this study is to determine whether Panax Notoginseng (PNG) taken for 3 days and one 30-min cycling exercise can reduce postprandial hyperglycemia after ingesting a 75-mg oral glucose solution (OGTT) in untrained non-diabetic men, age 20-45 years. We randomly assigned 52 men to: 1) ginseng (G) + exercise (G+Ex, n=14), 2) ginseng (G, n=13), 3) placebo (C) + exercise (C+Ex, n=12), and 4) placebo control groups (C, n=13). The G and C groups took a daily 3g dose of PNG and cornstarch-placebo supplement for 3 days, respectively. The exercise groups also performed a 30-min cycling exercise on day 3 prior to OGTT. The daily 3g-dose of PNG supplementation significantly lowered postprandial plasma glucose (PG) concentration at 30 min post-OGTT in the G group, compared with C (mean Δ±SE: G vs. C = 26.3±11 mg/dl, p<0.05) and PG area under the curve (PG-AUC0-90) in the G and G+Ex groups, relative to the C (G vs. C = 96.5±42 and G+Ex vs. C = 85.2±41 mg/dl, both p<0.05). We conclude that a daily 3g-dose of PNG taken for 3 days, not one acute bout of 30-min cycling exercise at 60% VO2max, lowered postprandial glycemia at 30-min post-OGTT and PG-AUC 0-90 min in non-diabetic men, age 20-45 years.

Effect of short-term upper-body resistance training on muscular strength, bone metabolic markers, and BMD in premenopausal women.

UNLABELLED: To examine the effect of a 10-week upper-body resistance training program on bone turnover markers and site-specific bone mineral density (BMD) in the wrist and distal half of the ulna and radius in untrained and healthy young premenopausal women. METHODS: Twenty-two subjects (aged 22.1 ± 1.8 years) were randomly assigned to a resistance training (n = 12) or no training control (n = 10) group. The following outcome variables were measured before and after 10 weeks of resistance training: (1) bone formation biomarker osteocalcin, and bone resorption biomarker tartrate-resistant acid phosphatase isoform 5b; (2) BMD in the wrist and distal half of the ulna and radius; (3) isokinetic strength of the elbow and knee extensors and flexors; (4) dynamic strength of the arm extensors and flexors; and (5) maximum number of push-ups. RESULTS: The 10-week upper body resistance training intervention resulted in improved strength performance in push-ups (resistance training versus control: P < 0.05), chest presses (P < 0.05), and pulldowns (P < 0.05). However, there was no improvement in the BMD of the wrist (P > 0.05), BMD of the distal half of the ulna and radius (P > 0.05), and metabolic biomarkers osteocalcin (P > 0.05) and tartrate-resistant acid phosphatase isoform 5b (P > 0.05), except for the osteocalcin/tartrate-resistant acid phosphatase isoform 5b ratio. Also, no improvement in the resistance training group was observed for isokinetic strength of the knee and elbow flexion/extension. CONCLUSION: Upper-body muscular strength performance, but not bone metabolic markers and BMD of the wrist, can be improved with a 10-week upper body resistance training program of the nonweight-bearing limbs in untrained young premenopausal women.

Caffeine use in sports: considerations for the athlete.

The ergogenic effects of caffeine on athletic performance have been shown in many studies, and its broad range of metabolic, hormonal, and physiologic effects has been recorded, as this review of the literature shows. However, few caffeine studies have been published to include cognitive and physiologic considerations for the athlete. The following practical recommendations consider the global effects of caffeine on the body: Lower doses can be as effective as higher doses during exercise performance without any negative coincidence; after a period of cessation, restarting caffeine intake at a low amount before performance can provide the same ergogenic effects as acute intake; caffeine can be taken gradually at low doses to avoid tolerance during the course of 3 or 4 days, just before intense training to sustain exercise intensity; and caffeine can improve cognitive aspects of performance, such as concentration, when an athlete has not slept well. Athletes and coaches also must consider how a person's body size, age, gender, previous use, level of tolerance, and the dose itself all influence the ergogenic effects of caffeine on sports performance.

Pituitary-adrenal responses to arm versus leg exercise in untrained man.

The purpose of this study was to examine pituitary-adrenal (PA) hormone responses [beta-endorphin (beta-END), adrenocorticotropic hormone (ACTH) and cortisol] to arm exercise (AE) and leg exercise (LE) at 60 and 80% of the muscle-group specific VO2 peak. Eight healthy untrained men (AE VO2 peak=32.4+/-3.0 ml kg(-1) min(-1), LE VO2 peak=46.9+/-5.3 ml kg(-1) min(-1)) performed two sub-maximal AE and LE tests in random order. Plasma beta-END, ACTH and cortisol were not different (P>0.05) between AE and LE at either exercise intensity; the 60% testing elicited no changes from pre-exercise (PRE) values. For 80% testing, plasma beta-END, ACTH and cortisol were consistently, but not significantly, greater during LE than AE. In general, plasma beta-END and ACTH were higher (P<0.05) during 80% exercise, than PRE, for both AE and LE. Plasma cortisol was elevated (P<0.05) above PRE during 80% LE, and following 80% for both AE and LE. Plasma ACTH was higher (P<0.05) during 80% LE and AE versus 60% LE and AE, respectively. Plasma beta-END and cortisol were significantly higher during and immediately after 80% LE than 60% LE. Thus, plasma beta-END, ACTH and cortisol responses were similar for AE and LE at the two relative exercise intensities, with the intensity threshold occurring somewhere between 60 and 80% of VO2 peak. It appears that the smaller muscle mass associated with AE was sufficient to stimulate these PA axis hormones in a manner similar to LE, despite the higher metabolic stress (i.e., plasma La-) associated with LE.

Fluid, electrolyte, and renal indices of hydration during 11 days of controlled caffeine consumption.

This investigation determined if 3 levels of controlled caffeine consumption affected fluid-electrolyte balance and renal function differently. Healthy males (mean +/- standard deviation; age, 21.6 +/- 3.3 y) consumed 3 mg caffeine . kg(-1) . d(-1). on days 1 to 6 (equilibration phase). On days 7 to 11 (treatment phase), subjects consumed either 0 mg (C0; placebo; n= 20), 3 mg (C3; n = 20), or 6 mg (C6; n = 19) caffeine . kg(-1) . d(-1) in capsules, with no other dietary caffeine intake. The following variables were unaffected (P > 0.05) by different caffeine doses on days 1, 3, 6, 9, and 11 and were within normal clinical ranges: body mass, urine osmolality, urine specific gravity, urine color, 24-h urine volume, 24-h Na+ and K+ excretion, 24-h creatinine, blood urea nitrogen, serum Na+ and K+, serum osmolality, hematocrit, and total plasma protein. Therefore, C0, C3, and C6 exhibited no evidence of hypohydration. These findings question the widely accepted notion that caffeine consumption acts chronically as a diuretic.

Effect of chronic caffeine intake on choice reaction time, mood, and visual vigilance.

The stimulatory effects of acute caffeine intake on choice reaction time, mood state, and visual vigilance are well established. Little research exists, however, on the effects of chronic caffeine ingestion on psychomotor tasks. Therefore, the purpose of this study was to evaluate the effects of 5 days of controlled caffeine intake on cognitive and psychomotor performance. Three groups of 20 healthy males (age=22+/-3 years, mass=75.4+/-7.9 kg, body fat percentage=11.2+/-5.1%) twice completed a battery of cognitive and psychomotor tasks: after 6 days of 3 mg.kg(-1) day(-1) caffeine equilibration (Day 6), and after 5 days of experimental (0 [G0], 3 [G3], or 6 [G6] mg.kg(-1) day(-1)) caffeine intake (Day 11). Groups were randomized and stratified for age, mass, and body composition; all procedures were double-blind. Cognitive analyses involved a visual four-choice reaction time test, a mood state questionnaire, and a visual vigilance task. Experimental chronic caffeine intake did not significantly alter the number of correct responses or the mean latency of response for either the four-choice reaction time or the visual vigilance tasks. The Vigor-Activity subset of the mood state questionnaire was significantly greater in G3 than G0 or G6 on Day 11. All other mood constructs were unaffected by caffeine intake. In conclusion, few cognitive and psychomotor differences existed after 5 days of controlled caffeine ingestion between subjects consuming 0, 3, or 6 mg.kg(-1) day(-1) of caffeine, suggesting that chronic caffeine intake (1) has few perceptible effects on cognitive and psychomotor well-being and (2) may lead to a tolerance to some aspects of caffeine's acute effects.