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Thomas I. Gee, Duncan N. French, Karl C. Gibbon and Kevin G. Thompson

Purpose:

This study investigated the pacing strategy adopted and the consistency of performance and related physiological parameters across three 2000-m rowing-ergometer tests.

Methods:

Fourteen male well-trained rowers took part in the study. Each participant performed three 2000-m rowing-ergometer tests interspersed by 3–7 d. Throughout the trials, respiratory exchange and heart rate were recorded and power output and stroke rate were analyzed over each 500 m of the test. At the completion of the trial, assessments of blood lactate and rating of perceived exertion were measured.

Results:

Ergometer performance was unchanged across the 3 trials; however, pacing strategy changed from trial 1, which featured a higher starting power output and more progressive decrease in power, to trials 2 and 3, which were characterized by a more conservative start and an end spurt with increased power output during the final 500 m. Mean typical error (TE; %) across the three 2000-m trials was 2.4%, and variability was low to moderate for all assessed physiological variables (TE range = 1.4−5.1%) with the exception of peak lactate (TE = 11.5%).

Conclusions:

Performance and physiological responses during 2000-m rowing ergometry were found to be consistent over 3 trials. The variations observed in pacing strategy between trial 1 and trials 2 and 3 suggest that a habituation trial is required before an intervention study and that participants move from a positive to a reverse-J-shaped strategy, which may partly explain conflicting reports in the pacing strategy exhibited during 2000-m rowing-ergometer trials.

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Laura Capranica and Mindy L. Millard-Stafford

A prevailing theory (and practical application) is that elite performance requires early childhood skill development and training across various domains, including sport. Debate continues whether children specializing early (ie, training/competition in a single sport) have true advantage compared with those who sample various sports early and specialize in a single sport later (adolescence). Retrospective data and case studies suggest either model yields elite status depending upon the sport category (ie, situational: ball games, martial arts, fencing; quantitative: track and feld, swimming, skiing; or qualitative: gymnastics, diving, figure skating). However, potential risks of early specialization include greater attrition and adverse physical/emotional health outcomes. With the advent of the IOC Youth Olympic Games, increased emphasis on global youth competition has unknown implications but also represents a potential platform for investigation. Modification of youth competition formats should be based upon multidisciplinary research on psycho-physiological responses, and technical-tactical behaviors during competition. The assumption that a simple scaled-down approach of adult competitions facilitates the development of technical/tactical skills of youth athletes is not necessarily substantiated with field-based research. Relatively little evidence exists regarding the long-term effects of rigorous training and competitive schedules on children in specific sports. It is clear that more prospective studies are needed to understand the training dose that optimally develops adaptations in youth without inducing dropout, overtraining syndrome, and/or injury. Such an approach should be sport specific as well as gender based. Until such evidence exists, coaches and sport administrators will continue to rely upon their sport-specific dogma to influence programmatic development of our most vulnerable population.

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Jocelyn K. Mara, Kevin G. Thompson and Kate L. Pumpa

Purpose:

To investigate the physical and physiological response to different formats of various-sided games.

Methods:

Eighteen elite women’s soccer players wore 15-Hz global positioning system devices and heart-rate (HR) monitors during various-sided games (small, 4 vs 4 and 5 vs 5; medium, 6 vs 6 and 7 vs 7; large, 8 vs 8 and 9 vs 9).

Results:

Players covered more relative sprinting distance during large-sided games than in small-sided (P < .001, d = 0.69) and medium-sided (P < .001, d = 0.54) games. In addition, a greater proportion of total acceleration efforts that had a commencement velocity <1 m/s were observed in small-sided games (44.7% ± 5.5%) than in large-sided games (36.7% ± 10.6%) (P = .018, d = 0.94). This was accompanied by a greater proportion of acceleration efforts with a final velocity equivalent to the sprint threshold in large-sided games (15.4% ± 7.7%) than in small-sided games (5.2% ± 2.5%) (P < .001, d = 1.78). The proportion of time spent in HR zone 4 (>85% maximum HR) was greater during small-sided games (69.8% ± 2.5%) than in medium- (62.1% ± 2.8%, d = 2.90) and large-sided games (54.9% ± 3.1%) (P < .001, d = 5.29).

Conclusions:

The results from this study demonstrate that coaches can use small-sided games as an aerobic conditioning stimulus and to develop players’ explosiveness and repeat-sprint ability over short durations. Large-sided games can be used to maintain aerobic capacity and develop maximum speed over longer distances.

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Michael J. Hartman, Brandon Clark, Debra A. Bemben, J. Lon Kilgore and Michael G. Bemben

Context:

Many elite athletes use increased daily training frequencies as a means to increase training load without substantial published literature to support this practice.

Purpose:

To compare the physiological responses to twice- and once-daily training sessions with similar training volumes.

Methods:

Ten nationally competitive male weightlifters (age 20.5 ± 1.2 y, body mass 92.9 ± 23.6 kg, training history 5.5 ± 1.5 y) were matched on body mass and training experience, then randomly assigned to train either once or twice daily for 3 wk. Isometric knee-extension strength (ISO), muscle cross-sectional area, vertical-jump peak power, resting hormone concentrations, neuromuscular activation (EMG), and weightlifting performance were obtained before and after the experimental training period.

Results:

All dependent measures before the training intervention were similar for both groups. A 2-way repeated-measures ANOVA did not reveal any significant main effects (group or trial) or interaction effects (group × trial) for any of the dependent variables. There were also no significant group differences when parameters were expressed as percentage change, but the twice-daily training group had a greater percentage change in ISO (+5.1% vs +3.2%), EMG (+20.3% vs +9.1%), testosterone (+10.5% vs +6.4%), and testosterone:cortisol ratio (−10.5% vs +1.3%) than did the once-daily training group.

Conclusions:

There were no additional benefits from increased daily training frequency in national-level male weightlifters, but the increase in ISO and EMG activity for the twice-daily group might provide some rationale for dividing training load in an attempt to reduce the risk of overtraining.

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Mohamed Ali Nabli, Nidhal Ben Abdelkrim, Imed Jabri, Tahar Batikh, Carlo Castagna and Karim Chamari

Purpose:

To examine the relation between game performance, physiological responses, and field-test results in Tunisian basketball referees.

Methods:

Computerized time–motion analysis, heart rate (HR), and blood lactate concentration [La] were measured in 15 referees during 8 competitive games (under-19-y-old Tunisian league). Referees also performed a repeated-sprint test (RSA), Yo-Yo Intermittent Recovery Test level 1 (YYIRTL1), agility T-test, and 30-m sprint with 10-m lap time. Computerized video analysis determined the time spent in 5 locomotor activities (standing, walking, jogging, running, and sprint), then grouped in high-, moderate-, and low-intensity activities (HIAs, MIAs, and LIAs, respectively).

Results:

YYIRTL1 performance correlated with (1) total distance covered during the 4th quarter (r = .52, P = .04) and (2) distance covered in LIA during all game periods (P < .05). Both distance covered and time spent in MIA during the 1st quarter were negatively correlated with the YYIRTL1 performance (r = –.53, P = .035; r = –.67, P = .004, respectively). A negative correlation was found between distance covered at HIA during the 2nd half (3rd quarter + 4th quarter) and fatigue index of the RSA test (r = –.54, P = .029). Mean HR (expressed as %HRpeak) during all game periods was correlated with YYIRTL1 performance (.61 ≤ r < .67, P < .01).

Conclusions:

This study showed that (1) the YYIRTL1 performance is a moderate predictor of game physical performance in U-19 basketball referees and (2) referees’ RSA correlates with the amount of HIA performed during the 2nd half, which represents the ability to keep up with play.

Open access

Stephen Seiler and Øystein Sylta

The purpose of this study was to compare physiological responses and perceived exertion among well-trained cyclists (n = 63) performing 3 different high-intensity interval-training (HIIT) prescriptions differing in work-bout duration and accumulated duration but all prescribed with maximal session effort. Subjects (male, mean ± SD 38 ± 8 y, VO2peak 62 ± 6 mL · kg–1 · min–1) completed up to 24 HIIT sessions over 12 wk as part of a training-intervention study. Sessions were prescribed as 4 × 16, 4 × 8, or 4 × 4 min with 2-min recovery periods (8 sessions of each prescription, balanced over time). Power output, HR, and RPE were collected during and after each work bout. Session RPE was reported after each session. Blood lactate samples were collected throughout the 12 wk. Physiological and perceptual responses during >1400 training sessions were analyzed. HIIT sessions were performed at 95% ± 5%, 106% ± 5%, and 117% ± 6% of 40-min time-trial power during 4 × 16-, 4 × 8-, and 4 × 4-min sessions, respectively, with peak HR in each work bout averaging 89% ± 2%, 91% ± 2%, and 94% ± 2% HRpeak. Blood lactate concentrations were 4.7 ± 1.6, 9.2 ± 2.4, and 12.7 ± 2.7 mmol/L. Despite the common prescription of maximal session effort, RPE and sRPE increased with decreasing accumulated work duration (AWD), tracking relative HR. Only 8% of 4 × 16-min sessions reached RPE 19–20, vs 61% of 4 × 4-min sessions. The authors conclude that within the HIIT duration range, performing at “maximal session effort” over a reduced AWD is associated with higher perceived exertion both acutely and postexercise. This may have important implications for HIIT prescription choices.

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Sonya L. Cameron, Rebecca T. McLay-Cooke, Rachel C. Brown, Andrew R. Gray and Kirsty A. Fairbairn

Purpose:

This study investigated the effect of ingesting 0.3 g/kg body weight (BW) of sodium bicarbonate (NaHCO3) on physiological responses, gastrointestinal (GI) tolerability, and sprint performance in elite rugby union players.

Methods:

Twenty-five male rugby players, age 21.6 (2.6) yr, participated in a randomized, double-blind, placebo-controlled crossover trial. Sixty-five minutes after consuming 0.3 g/kg BW of either NaHCO3 or placebo, participants completed a 25-min warm-up followed by 9 min of high-intensity rugby-specific training followed by a rugby-specific repeated-sprint test (RSRST). Whole-blood samples were collected to determine lactate and bicarbonate concentrations and pH at baseline, after supplement ingestion, and immediately after the RSRST. Acute GI discomfort was assessed by questionnaire throughout the trials, and chronic GI discomfort was assessed during the 24 hr postingestion.

Results:

After supplement ingestion and immediately after the RSRST, blood HCO3 concentration and pH were higher for the NaHCO3 condition than for the placebo condition (p < .001). After the RSRST, blood lactate concentrations were significantly higher for the NaHCO3 than for the placebo condition (p < .001). There was no difference in performance on the RSRST between the 2 conditions. The incidence of belching, stomachache, diarrhea, stomach bloating, and nausea was higher after ingestion of NaHCO3 than with placebo (all p < .050). The severity of stomach cramps, belching, stomachache, bowel urgency, diarrhea, vomiting, stomach bloating, and flatulence was rated worse after ingestion of NaHCO3 than with placebo (p < .050).

Conclusions:

NaHCO3 supplementation increased blood HCO3 concentration and attenuated the decline in blood pH compared with placebo during high-intensity exercise in well-trained rugby players but did not significantly improve exercise performance. The higher incidence and greater severity of GI symptoms after ingestion of NaHCO3 may negatively affect physical performance, and the authors strongly recommend testing this supplement during training before use in competitive situations.

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Alexandre Dellal, Carlos Lago-Penas, Del P. Wong and Karim Chamari

Purpose:

The aim of this study was to examine the influence of the number of ball touches authorized per possession on the physical demands, technical performances and physiological responses throughout the bouts within 4 vs. 4 soccer small-sided games (SSGs).

Methods:

Twenty international soccer players (27.4 ± 1.5 y, 180.6 ± 2.3 cm, 79.2 ± 4.2 kg, body fat 12.7 ± 1.2%) performed three different 4 vs. 4 SSGs (4 × 4 min) in which the number of ball touches authorized per possession was manipulated (1 touch = 1T; 2 touches = 2T; Free Play = FP). The SSGs were divided in 4 bouts (B1, B2, B3 and B4) separated by 3 min of passive recovery. The physical performances, technical activities, heart rate responses, blood lactate and RPE were analyzed.

Results:

The FP rule presented greater number of duels, induced the lowest decreases of the sprint and high-intensity performances, and affected less the technical actions (successful passes and number of ball losses) from B1 to B4 as compared with 1T and 2T forms. Moreover, the SSG played in 1T form led to reach higher solicitation of the high-intensity actions while players presented more difficulty to perform a correct technical action.

Conclusions:

The modification of the number of ball touches authorized per possession affects the soccer player activity from the first to the last bout of SSG, indicating that the determination of this rule has to be precisely planned by the coach according to the objectives of the training.

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Sara Dean, Andrea Braakhuis and Carl Paton

Researchers have long been investigating strategies that can increase athletes’ ability to oxidize fatty acids and spare carbohydrate, thus potentially improving endurance capacity. Green-tea extract (epigallocatechin-3-gallate; EGCG) has been shown to improve endurance capacity in mice. If a green-tea extract can stimulate fat oxidation and as a result spare glycogen stores, then athletes may benefit through improved endurance performance. Eight male cyclists completed a study incorporating a 3-way crossover, randomized, placebo-controlled, double-blinded, diet-controlled research design. All participants received 3 different treatments (placebo 270 mg, EGCG 270 mg, and placebo 270 mg + caffeine 3 mg/kg) over a 6-day period and 1 hr before exercise testing. Each participant completed 3 exercise trials consisting of 60 min of cycling at 60% maximum oxygen uptake (VO2max) immediately followed by a self-paced 40-km cycling time trial. The study found little benefit in consuming green-tea extract on fat oxidation or cycling performance, unlike caffeine, which did benefit cycling performance. The physiological responses observed during submaximal cycling after caffeine ingestion were similar to those reported previously, including an increase in heart rate (EGCG 147 ± 17, caffeine 146 ± 19, and placebo 144 ± 15 beats/min), glucose at the 40-min exercise time point (placebo 5.0 ± 0.8, EGCG 5.4 ± 1.0, and caffeine 5.8 ± 1.0 mmol/L), and resting plasma free fatty acids and no change in the amount of carbohydrate and fat being oxidized. Therefore, it was concluded that green-tea extract offers no additional benefit to cyclists over and above those achieved by using caffeine.

Open access

Øyvind Sandbakk

validating or using technology to gain valuable insights into sport physiology and performance. Technology-driven digital solutions may provide knowledge beyond what standard measurements have previously allowed. Positioning systems, inertial movement units, and various sensors that measure physiological