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Jason Brandenburg and David Docherty

Purpose:

To examine the acute response to 2 resistance-exercise protocols performed to repetition failure, but different in load configuration, and determine whether the acute response was related to strength increases after 8 weeks of training.

Methods:

Eighteen resistance-trained men completed a single session of 2 resistance-exercise protocols. The constant-load protocol (CL) required subjects to complete 3 sets of single-arm preacher curls (elbow flexion) to failure using a load of ~77% 1RM. The reduced-load protocol (RL) was similar, but training load was reduced for the second and third sets. Maximal isometric force (MVIC) and blood lactate were assessed preprotocol and postprotocol to determine the acute response. For the 8-week training phase, subjects (N = 12) were divided into 2 programs, each corresponsing to 1 of the protocols. Strength was measured before and after training.

Results:

MVIC decreased from 106.2 ± 13.8 to 84.3 ± 12.1 N · m and from 109.1 ± 14.7 to 82.5 ± 13 N · m after the CL and RL protocols, respectively. The decrements in MVIC were significant (P < .001), with the decline after RL tending to be greater (P = .051). Postprotocol blood lactate concentrations after CL and RL were 3.4 ± 1.1 and 4.1 ± 1.3 mmol/L, respectively, with greater increases after RL (P = .036). Similar and significant 1RM strength increases were observed after both programs (from 20.7 ± 2.7 to 23.3 ± 3.5 kg after CL and from 22.4 ± 2.9 to 25.5 ± 3.2 kg after RL; P < .001).

Conclusion:

The similar increases in strength suggest that either the greater acute response to RL was not related to the increases in strength or a minimal (threshold) response was achieved during both programs.

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Jason P. Brandenburg and Michael Gaetz

This study determined the fluid balance of elite female basketball players before and during competition. Before and during 2 international games, 17 national-level players (age 24.2 ± 3 yr, height 180.5 ± 6 cm, mass 78.8 ± 8 kg) were assessed. Fluid-balance assessment included pregame hydration level as determined by urine specific gravity (USG), change in body mass during the game, ad libitum intake of water or sports drink, and estimated sweat losses. Mean (± SD) USG before Game 1 was 1.005 ± 0.002 and before Game 2 USG equaled 1.010 ± 0.005. Players lost an average of 0.7% ± 0.8% and 0.6% ± 0.6% of their body mass during Games 1 and 2, respectively. In each game, 3 players experienced a fluid deficit >1% of body mass, and 1 other, a fluid deficit >2%. Sweat losses in both games, from the beginning of the warm-up to the conclusion of the game (~125 min with average playing time 16–17 min), were approximately 1.99 ± 0.75 L. Fluid intake in Game 1 and Game 2 equaled 77.8% ± 32% and 78.0% ± 21% of sweat losses, respectively. Most players were hydrated before each game and did not become meaningfully dehydrated during the game. It is possible that the players who experienced the highest levels of dehydration also experienced some degree of playing impairment, and the negative relationship between change in body mass and shooting percentage in Game 2 provides some support for this notion.

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Jason P. Brandenburg and Luisa V. Giles

Blueberries are abundant with anthocyanins possessing antioxidant and anti-inflammatory properties. As these properties combat fatigue and promote recovery, blueberry supplementation may enhance performance and recovery. Thus, the objectives were to examine the effects of two blueberry supplementation protocols on running performance, physiological responses, and short-term recovery. Using a randomized, double-blind, placebo (PLA)-controlled crossover design, 14 runners completed an 8-km time trial (TT) after supplementation with 4 days of blueberries (4DAY), 4 days of a PLA, or 2 days of placebo followed by 2 days of blueberries (2DAY). Heart rate and ratings of perceived exertion were monitored during the TT. Blood lactate, vertical jump, reactive strength index, and salivary markers were assessed before and after. No significant differences were observed for time to complete the TT (PLA: 3,010 ± 459 s; 2DAY: 3,014 ± 488 s; 4DAY: 3,011 ± 423 s), heart rate, ratings of perceived exertion, or any of the salivary markers. An interaction effect (p = .027) was observed for blood lactate, with lower post-TT concentrations in 4DAY (5.4 ± 2.0 mmol/L) than PLA (6.6 ± 2.5 mmol/L; p = .038) and 2DAY (7.4 ± 3.4 mmol/L; p = .034). Post-TT decreases in vertical jump height were not different, whereas the decline in reactive strength index was less following 4DAY (−6.1% ± 13.5%) than the other conditions (PLA: −12.6% ± 10.1%; 2DAY: −11.6% ± 11.5%; p = .038). Two days of supplementation did not influence performance or physiological stress. Although 4 days of supplementation did not alter performance, it blunted the increase in blood lactate, perhaps reflecting altered lactate production and/or clearance, and offset the decrease in dynamic muscle function post-TT, as indicated by the reactive strength index differences.

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Norman S. Hannibal III, Sharon Ann Plowman, Marilyn A. Looney and Jason Brandenburg

Background:

Strength, muscular endurance, and flexibility are important components of healthy back function. This study determined the reliability and evaluated the validity of selected low back field tests (FITNESSGRAM ® Trunk Extension [FG-TE] and Box 90° Dynamic Trunk Extension [B-90° DTE]) when compared to laboratory tests (Parallel Roman Chair Dynamic Trunk Extension [PRC-DTE], Parallel Roman Chair Static Trunk Extension [PRC-STE], and Dynamometer Static Back Lift [DSBL]).

Methods:

Forty males age 15.1 ± 1.2 yr and 32 females age 15.5 ± 1.2 yr participated.

Results:

Intraclass test-retest reliability coefficients (one-way ANOVA model for a single measure) ranged from .940 to .996. Validity coefficients determined by Pearson product moment correlation coefficients for males and females, respectively, were as follows: B-90° DTE vs. PRC-DTE = .82, .62 (p < .05); B-90° DTE vs. PRC-STE = .55, .38 (p < .05); B-90° DTE vs. DSBL = −.29, −.23; FG-TE vs. PRC-DTE = .23, −.11; FG-TE vs. PRC-STE = −.15, .33; and FG-TE vs. DSBL = −.04, −.36.

Conclusions:

B-90° DTE was shown to be a valid field test when compared to PRC-DTE, but only for the males. Further research on the PRC-DTE and PRC-STE items for adolescents is recommended.

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Jason Brandenburg, William A. Pitney, Paul E. Luebbers, Arun Veera and Alicja Czajka

Purpose:

To examine the acute effects of static stretching on countermovement vertical-jump (CMVJ) ability and monitor the time course of any stretch-induced changes.

Methods:

Once familiarized, 16 experienced jumpers completed 2 testing sessions in a randomized order. Each session consisted of a general warm-up, a pretreatment CMVJ assessment, a treatment, and multiple posttreatment CMVJ assessments. One treatment included lower-body static stretching, and the second treatment, involving no stretching, was the control. Posttreatment CMVJ measures occurred immediately, 3, 6, 12, and 24 minutes posttreatment. Stretching consisted of 3 static-stretching exercises, with each exercise repeated 3 times and each repetition held for 30 s.

Results:

Prestretch CMVJ height equaled 47.1 (± 9.7) cm. CMVJ height immediately poststretch was 45.7 (± 9.2) cm, and it remained depressed during the 24-min follow-up period. Pre-no-stretch CMVJ height was 48.4 (± 9.8) cm, whereas immediately post-no-stretch CMVJ height equaled 46.8 (± 9.5) cm, and as in the stretch treatment, post-no-stretch CMVJ height remained lower than pre-no-stretch values. Although there was a significant main effect of time (P = .005), indicating that CMVJ was lower and remained impaired after both treatments, no significant interaction effect (P = .749) was observed.

Conclusion:

In comparison with the no-activity control, static stretching resulted in similar reductions in CMVJ ability when examined over the same time course, so athletes preparing for CMVJ should avoid periods of inactivity, as well as static stretching.