Abstract: The present study investigated the effect of ingesting caffeine-dose-matched anhydrous caffeine or coffee on the performance of repeated sprints. Twelve recreationally active males (mean ± SD age: 22 ± 2 years, height: 1.78 ± 0.07 m, body mass: 81 ± 16 kg) completed eighteen 4 s sprints with 116 s recovery on a cycle ergometer on four separate occasions in a double-blind, randomised, counterbalanced crossover design. Participants ingested either 3 mg·kg−1 of caffeine (CAF), 0.09 g·kg−1 coffee, which provided 3 mg·kg−1 of caffeine (COF), a taste-matched placebo beverage (PLA), or a control condition (CON) 45 min prior to commencing the exercise protocol. Peak and mean power output and rating of perceived exertion (RPE) were recorded for each sprint. There were no significant differences in peak power output (CAF: 949 ± 199 W, COF: 949 ± 174 W, PLA: 971 ± 149 W and CON: 975 ± 170 W; p = 0.872; = 0.02) or mean power output (CAF: 873 ± 172 W, COF: 862 ± 44 W, PLA: 887 ± 119 W and CON: 892 ± 143 W; p = 0.819; = 0.03) between experimental conditions. Mean RPE was similar for all trials (CAF: 11 ± 2, COF: 11 ± 2, PLA: 11 ± 2 and CON: 11 ± 2; p = 0.927; = 0.01). Neither the ingestion of COF or CAF improved repeated sprint cycling performance in relatively untrained males.
Abstract: The Star Excursion Balance Test (SEBT) is effective in measuring dynamic postural control (DPC). This research aimed to determine whether DPC measured by the SEBT in young athletes (YA) with back pain (BP) is different from those without BP (NBP). 53 BP YA and 53 NBP YA matched for age, height, weight, training years, training sessions/week and training minutes/session were studied. Participants performed 4 practice trials after which 3 measurements in the anterior, posteromedial and posterolateral SEBT reach directions were recorded. Normalized reach distance was analyzed using the mean of all 3 measurements. There was no statistical significant difference (p > 0.05) between the reach distance of BP (87.2 ± 5.3, 82.4 ± 8.2, 78.7 ± 8.1) and NBP (87.8 ± 5.6, 82.4 ± 8.0, 80.0 ± 8.8) in the anterior, posteromedial and posterolateral directions respectively. DPC in YA with BP, as assessed by the SEBT, was not different from NBP YA.
Abstract: Limited research exists comparing sex differences in muscular power. The primary purpose of this research was to determine if differences exist in power and velocity in the conventional deadlift (CDL). A secondary purpose was to examine the relationship among power, velocity, strength, and fat free mass (FFM). Eighteen strength trained athletes with ≥1 year CDL experience (women: n = 9, 29 ± 2 years, 162.3 ± 1.8 cm, 62 ± 2.4 kg, 23.3 ± 3.2 % body fat (%BF); men: n = 9, 29 ± 3 years, 175.6 ± 1.8 cm, 85.5 ± 1.4 kg, 14.8 ± 2.4 %BF), and ≥1.5 one repetition maximum (1-RM) CDL: body mass (BM) ratio (women: 1.6 ± 0.1 1-RM CDL: BM; men: 2.3 ± 0.1 1-RM CDL: BM), performed baseline (body composition, 1-RM CDL) and experimental sessions, in which velocity and power were measured at 30%, 60%, and 90% 1-RM. Repeated measures ANOVA and bivariate correlations were conducted. Men produced higher absolute average and peak power across all loads, but higher average velocity at only 30% 1-RM. When normalized to FFM, men produced higher peak and average power; however, women produced higher peak and average velocities across all loads. FFM and 1-RM were correlated with power. Greater power observed in men is driven by larger muscle mass, which contributes to greater strength.
Abstract: New Zealand blackcurrant (NZBC) extract has been shown to enhance high-intensity intermittent treadmill running. We examined the effects of NZBC extract during the Loughborough Intermittent Shuttle Test (LIST) which involves 5 × 15 min blocks with intermittent 15-m maximal sprints, interspersed by moderate and high-intensity running to simulate team sport activity, and a subsequent run to exhaustion. Thirteen males (age: 22 ± 1 year, : 50 ± 5 mL·kg−1·min−1) participated in three indoor sessions (T: 24 ± 3 °C, humidity: 52% ± 9%). In the first session, a multistage fitness test was completed to determine peak running speed and estimate . Participants consumed NZBC extract in capsules (300 mg·day−1 CurraNZ™) or placebo (PL) (300 mg·day−1 microcrystalline cellulose M102) for seven days in a double-blind, randomized, cross-over design (wash-out at least seven days). NZBC extract did not affect average 15-m sprint times in each block. NZBC reduced slowing of the fastest sprint between block 1 and 5 (PL: 0.12 ± 0.07 s; NZBC: 0.06 ± 0.12 s; p < 0.05). NZBC extract had no effect on heart rate, vertical jump power, lactate and time to exhaustion (PL: 13.44 ± 8.09 min, NZBC: 15.78 ± 9.40 min, p > 0.05). However, eight participants had higher running times to exhaustion when consuming NZBC extract. New Zealand blackcurrant extract may enhance performance in team sports with repeated maximal sprints.
Abstract: This study profiled junior college football players. Sixty-two subjects completed vertical jump (VJ; height and peak power), standing broad jump (SBJ), 36.58 m sprint, pro-agility shuttle, three-cone drill, and maximal-repetition bench press and front squat. The sample included 2 quarterbacks (QB), 7 running backs (RB), 13 wide receivers (WR), 1 tight end (TE), 18 defensive backs (DB), 8 linebackers (LB), and 13 offensive and defensive linemen (LM). To investigate positional differences, subjects were split into skill (SK; WR, DB), big skill (BSK; QB, RB, TE, LB), and LM groups. A one-way ANOVA determined between-group differences. LM were taller and heavier than SK and BSK players. The SK and BSK groups were faster than LM in the 0–36.58 m sprint, pro-agility shuttle, and three-cone drill (p ≤ 0.009). The SK group had greater VJ height and SBJ distance; LM generated greater VJ peak power (p ≤ 0.022). There were no between-group differences in the strength endurance tests. Compared to Division I data, junior college players were smaller, slower, and performed worse in jump tests. Positional differences in junior college football are typical to that of established research. Junior college players should attempt to increase body mass, and improve speed and lower-body power.
Abstract: This study aimed to determine the effects of a betalain-rich concentrate (BRC) of red beets, containing antioxidant and anti-inflammatory properties, on performance and exercise-related muscle damage. Thirteen (25.3 ± 5.4 years) competitive male runners completed two double-blind, cross-over, randomized trials (BRC and control) separated by seven days. Each trial was preceded by six days of supplementation with 100 mg of BRC or control. On the seventh day, exercise trials commenced 150 min after supplementation with 50 mg BRC or control and consisted of 30 min of treadmill running (77 ± 4% VO2max) followed by a 5-km time trial (TT). During exercise at the same intensity, BRC resulted in a 3% lower heart rate, a 15% lower rate of perceived exertion (RPE) and a 14% lower blood lactate concentration compared to the control (p = 0.05). Five-kilometer TT duration (23.0 ± 4.2 versus 23.6 ± 4.0 min) was faster in 10 of the 13 subjects, and RPE was lower (p < 0.05) with the BRC treatment compared to the control. Lactate dehydrogenase, a marker of muscle damage, increased less from baseline to immediately and 30 min after the 5-km TT with the BRC treatment, despite no differences in subjective measures of muscle soreness and fatigue. In summary, BRC supplementation improved 5-km performance time in male competitive runners.