markers; 6 however, no study has examined its usefulness in a football club setting. A particular advantage of the PRS is that it is synonymous with the rating of perceived exertion (RPE) (ie, 0–10 scale), a tool that is commonly used in football. Several studies have examined the time course of response
Darren J. Paul, Gustavo Tomazoli and George P. Nassis
Jason Brandenburg, William A. Pitney, Paul E. Luebbers, Arun Veera and Alicja Czajka
To examine the acute effects of static stretching on countermovement vertical-jump (CMVJ) ability and monitor the time course of any stretch-induced changes.
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.
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.
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.
Christopher J. Brush, Ryan L. Olson, Peter J. Ehmann, Steven Osovsky and Brandon L. Alderman
The purpose of this study was to examine possible dose–response and time course effects of an acute bout of resistance exercise on the core executive functions of inhibition, working memory, and cognitive flexibility. Twenty-eight participants (14 female; M age = 20.5 ± 2.1 years) completed a control condition and resistance exercise bouts performed at 40%, 70%, and 100% of their individual 10-repetition maximum. An executive function test battery was administered at 15 min and 180 min postexercise to assess immediate and delayed effects of exercise on executive functioning. At 15 min postexercise, high-intensity exercise resulted in less interference and improved reaction time (RT) for the Stroop task, while at 180 min low- and moderate-intensity exercise resulted in improved performance on plus–minus and Simon tasks, respectively. These findings suggest a limited and task-specific influence of acute resistance exercise on executive function in healthy young adults.
Hugh H.K. Fullagar, Andrew Govus, James Hanisch and Andrew Murray
To investigate the recovery time course of customized wellness markers (sleep, soreness, energy, and overall wellness) in response to match play in American Division I-A college football players.
A retrospective research design was used. Wellness data were collected and analyzed for 2 American college football seasons. Perceptions of soreness, sleep, energy, and overall wellness were obtained for the day before each game (GD–1) and the days after each game (GD+2, GD+3, and GD+4). Standardized effect-size (ES) analyses ± 90% confidence intervals were used to interpret the magnitude of the mean differences between all time points for the start, middle, and finish of the season, using the following qualitative descriptors: 0–0.19 trivial, 0.2–0.59 small, 0.6–1.19 moderate, 1.2–1.99 large, <2.0 very large.
Overall wellness showed small ES reductions on GD+2 (d = 0.22 ± 0.09, likely [94.8%]), GD+3 (d = 0.37 ± 0.15, very likely), and GD+4 (d = 0.29 ± 0.12, very likely) compared with GD–1. There were small ES reductions for soreness between GD–1 and GD+2, GD+3, and GD +4 (d = 0.21 ± 0.09, likely, d = 0.29 ± 0.12, very likely, and 0.30 ± 0.12, very likely, respectively). Small ES reductions were also evident between GD–1 and GD+3 (d = 0.21 ± 0.09, likely) for sleep. Feelings of energy showed small ESs on GD+3 (d = 0.27 ± 0.11, very likely) and GD+4 (d = 0.22 ± 0.09, likely) compared with GD–1.
All wellness markers were likely to very likely worse on GD+3 and GD+4 than on GD–1. These findings show that perceptual wellness takes longer than 4 d to return to pregame levels and thus should be considered when prescribing training and/or recovery.
Masatoshi Nakamura, Tome Ikezoe, Hiroki Umegaki, Takuya Kobayashi, Satoru Nishishita and Noriaki Ichihashi
Static stretching (SS) is commonly performed in a warm-up routine to increase joint range of motion (ROM) and to decrease muscle stiffness. However, the time course of changes in ankle-dorsiflexion (DF) ROM and muscle stiffness during a routine SS program is unclear.
To investigate changes in ankle-DF ROM, passive torque at DF ROM, and muscle stiffness during a routine SS program performed 3 times weekly for 4 wk.
A quasi-randomized controlled-trial design.
The subjects comprised 24 male volunteers (age 23.8 ± 2.3 y, height 172.0 ± 4.3 cm, body mass 63.1 ± 4.5 kg) randomly assigned to either a group performing a 4-wk stretching program (SS group) or a control group.
Main Outcome Measures:
DF ROM, passive torque, and muscle stiffness were measured during passive ankle dorsiflexion in both groups using a dynamometer and ultrasonography once weekly during the 4-wk intervention period.
In the SS group, DF ROM and passive torque at DF ROM significantly increased after 2, 3, and 4 wk compared with the initial measurements. Muscle stiffness also decreased significantly after 3 and 4 wk in the SS group. However, there were no significant changes in the control group.
Based on these results, the SS program effectively increased DF ROM and decreased muscle stiffness. Furthermore, an SS program of more than 2 wk duration effectively increased DF ROM and changed the stretch tolerance, and an SS program more than 3 wk in duration effectively decreased muscle stiffness.
Luana Farias de Oliveira, Bryan Saunders and Guilherme Giannini Artioli
Intensity (Number Outside Brackets) and Time Course (Number Inside Brackets) of SB Supplementation Side Effects SB1 SB2 SB3 PL Stomach problems None None None None Nausea None None None None Dizziness None None None None Headache None None 6 (200–240) None Flatulence 3 (140) None None None Urge to defecate
Mack D. Rubley, William R. Holcomb and Mark A. Guadagnoli
Cryotherapy is initially uncomfortable, but habituation is thought to occur during treatment.
To examine pain habituation to ice-bath immersion over 5 consecutive days.
Mean Borg ratings were analyzed by ANOVA.
Athletic training laboratory.
Ankle immersion in a 1 °C ice bath for 20 min.
28 healthy individuals.
Main Outcome Measure:
Level of discomfort was rated at immersion; during treatment at 1, 3, 5, 8, 11, 14, 17, and 20 min; and 1 min posttreatment.
Analysis revealed significant main effects for day and time and a Day × Time interaction. Day 1 had higher pain ratings than days 4 and 5. From min 1 to 11 there was a progressive decline in pain rating; after that there was no significant decline.
Discomfort was greatest during the first 5 min, and perception of discomfort at initial immersion was consistent across 5 days. In addition, after 3 days of treatments habituation occurred. Taken together, this suggests that treatment habituation is not the result of change in receptor sensitivity.
Rebecca Louise Jones, Trent Stellingwerff, Guilherme Giannini Artioli, Bryan Saunders, Simon Cooper and Craig Sale
To defend against hydrogen cation accumulation and muscle fatigue during exercise, sodium bicarbonate (NaHCO3) ingestion is commonplace. The individualized dose-response relationship between NaHCO3 ingestion and blood biochemistry is unclear. The present study investigated the bicarbonate, pH, base excess and sodium responses to NaHCO3 ingestion. Sixteen healthy males (23 ± 2 years; 78.6 ± 15.1 kg) attended three randomized order-balanced, nonblinded sessions, ingesting a single dose of either 0.1, 0.2 or 0.3 g·kg-1BM of NaHCO3 (Intralabs, UK). Fingertip capillary blood was obtained at baseline and every 10 min for 1 hr, then every 15 min for a further 2 hr. There was a significant main effect of both time and condition for all assessed blood analytes (p ≤ .001). Blood analyte responses were significantly lower following 0.1 g·kg-1BM compared with 0.2 g·kg-1BM; bicarbonate concentrations and base excess were highest following ingestion of 0.3 g·kg-1BM (p ≤ .01). Bicarbonate concentrations and pH significantly increased from baseline following all doses; the higher the dose the greater the increase. Large interindividual variability was shown in the magnitude of the increase in bicarbonate concentrations following each dose (+2.0–5; +5.1–8.1; and +6.0–12.3 mmol·L-1 for 0.1, 0.2 and 0.3 g·kg-1BM) and in the range of time to peak concentrations (30–150; 40–165; and 75–180 min for 0.1, 0.2 and 0.3 g·kg-1BM). The variability in bicarbonate responses was not affected by normalization to body mass. These results challenge current practices relating to NaHCO3 supplementation and clearly show the need for athletes to individualize their ingestion protocol and trial varying dosages before competition.
Michael J. Price and Malkit Singh
This study examined the increase in blood pH and bicarbonate concentration after ingestion of a standard sodium bicarbonate solution. Peak blood pH and bicarbonate concentration occurred between 60 and 90 minutes. Values decreased over the remainder of the ingestion period although still elevated above preingestion levels.