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Jace A. Delaney, Tannath J. Scott, Heidi R. Thornton, Kyle J.M. Bennett, David Gay, Grant M. Duthie and Ben J. Dascombe

Rugby league coaches often prescribe training to replicate the demands of competition. The intensities of running drills are often monitored in comparison with absolute match-play measures. Such measures may not be sensitive enough to detect fluctuations in intensity across a match or to differentiate between positions.

Purpose:

To determine the position- and duration-specific running intensities of rugby league competition, using a moving-average method, for the prescription and monitoring of training.

Methods:

Data from a 15-Hz global positioning system (GPS) were collected from 32 professional rugby league players across a season. The velocity–time curve was analyzed using a rolling-average method, where maximum values were calculated for 10 different durations, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 min, for each player across each match.

Results:

There were large differences between the 1- and 2-min rolling averages and all other rolling-average durations. Smaller differences were observed for rolling averages of greater duration. Fullbacks maintained a greater velocity than outside backs and middle and edge forwards over the 1- and 2-min rolling averages (ES 0.8−1.2, P < .05). For rolling averages 3 min and greater, the running demands of the fullbacks were greater than those of the middle forwards and outside backs (ES 1.1−1.4, P < .05).

Conclusions:

These findings suggest that the running demands of rugby league fluctuate vastly across a match. Fullbacks were the only position to exhibit a greater running intensity than any other position, and therefore training prescription should reflect this.

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Joel T. Fuller, Clint R. Bellenger, Dominic Thewlis, John Arnold, Rebecca L. Thomson, Margarita D. Tsiros, Eileen Y. Robertson and Jonathan D. Buckley

Purpose:

Stride-to-stride fluctuations in running-stride interval display long-range correlations that break down in the presence of fatigue accumulated during an exhaustive run. The purpose of the study was to investigate whether long-range correlations in running-stride interval were reduced by fatigue accumulated during prolonged exposure to a high training load (functional overreaching) and were associated with decrements in performance caused by functional overreaching.

Methods:

Ten trained male runners completed 7 d of light training (LT7), 14 d of heavy training (HT14) designed to induce a state of functional overreaching, and 10 d of light training (LT10) in a fixed order. Running-stride intervals and 5-km time-trial (5TT) performance were assessed after each training phase. The strength of long-range correlations in running-stride interval was assessed at 3 speeds (8, 10.5, and 13 km/h) using detrended fluctuation analysis.

Results:

Relative to performance post-LT7, time to complete the 5TT was increased after HT14 (+18 s; P < .05) and decreased after LT10 (–20 s; P = .03), but stride-interval long-range correlations remained unchanged at HT14 and LT10 (P > .50). Changes in stride-interval long-range correlations measured at a 10.5-km/h running speed were negatively associated with changes in 5TT performance (r –.46; P = .03).

Conclusions:

Runners who were most affected by the prolonged exposure to high training load (as evidenced by greater reductions in 5TT performance) experienced the greatest reductions in stride-interval long-range correlations. Measurement of stride-interval long-range correlations may be useful for monitoring the effect of high training loads on athlete performance.

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Everton C. do Carmo, Renato Barroso, Andrew Renfree, Saulo Gil and Valmor Tricoli

The effects of an enforced fast start on long-distance performance are controversial and seem to depend on the athlete’s capacity to delay and tolerate metabolic disruption. The aim of this study was to investigate the effects of an enforced start on 10-km-running performance and the influence of the some physiological and performance variables on the ability to tolerate an enforced fast start during the running. Fifteen moderately trained runners performed two 10-km time trials (TTs): free pacing (FP-TT) and fast start (FS-TT). During FS-TT, speed during the first kilometer was 6% higher than in FP-TT. Maximal oxygen uptake (VO2max), peak velocity (PV), velocity associated with VO2max (vVO2max), ventilatory threshold, and running economy at 10 and 12 km/h and FP-TT average velocity (AV-10 km) were individually determined. There were no differences between FP-TT and FS-TT performance (45:01 ± 4:08 vs 45:11 ± 4:46 min:s, respectively, P = .4). Eight participants improved (+2.2%) their performance and were classified as positive responders (PR) and 7 decreased (–3.3%) performance and were classified as negative responders (NR). Running speed was significantly higher for PR between 6 and 9.2 km (P < .05) during FS-TT. In addition, PR presented higher PV (P = .02) and vVO2max (P = .01) than NR, suggesting that PV and vVO2max might influence the ability to tolerate a fast-start strategy. In conclusion, there was an individual response to the enforced fast-start strategy during 10-km running, and those who improved performance also presented higher vVO2max and PV, suggesting a possible association between these variables and response to the strategy adopted.

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Ben J. Dascombe, Trent K. Hoare, Joshua A. Sear, Peter R. Reaburn and Aaron T. Scanlan

Purpose:

To examine whether wearing various size lower-body compression garments improves physiological and performance parameters related to endurance running in well-trained athletes.

Methods:

Eleven well-trained middle-distance runners and triathletes (age: 28.4 ± 10.0 y; height: 177.3 ± 4.7 cm; body mass: 72.6 ± 8.0 kg; VO2max: 59.0 ± 6.7 mL·kg–1·min–1) completed repeat progressive maximal tests (PMT) and time-to-exhaustion (TTE) tests at 90% VO2max wearing either manufacturer-recommended LBCG (rLBCG), undersized LBCG (uLBCG), or loose running shorts (CONT). During all exercise testing, several systemic and peripheral physiological measures were taken.

Results:

The results indicated similar effects of wearing rLBCG and uLBCG compared with the control. Across the PMT, wearing either LBCG resulted in significantly (P < .05) increased oxygen consumption, O2 pulse, and deoxyhemoglobin (HHb) and decreased running economy, oxyhemoglobin, and tissue oxygenation index (TOI) at low-intensity speeds (8–10 km·h–1). At higher speeds (12–18 km·h-1), wearing LBCG increased regional blood fow (nTHI) and HHb values, but significantly lowered heart rate and TOI. During the TTE, wearing either LBCG significantly (P < .05) increased HHb concentration, whereas wearing uLBCG also significantly (P < .05) increased nTHI. No improvement in endurance running performance was observed in either compression condition.

Conclusion:

The results suggest that wearing LBCG facilitated a small number of cardiorespiratory and peripheral physiological benefits that appeared mostly related to improvements in venous flow. However, these improvements appear trivial to athletes, as they did not correspond to any improvement in endurance running performance.

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Jordan Santos-Concejero, Jesús Oliván, José L. Maté-Muñoz, Carlos Muniesa, Marta Montil, Ross Tucker and Alejandro Lucia

Purpose:

This study aimed to determine whether biomechanical characteristics such as ground-contact time, swing time, and stride length and frequency contribute to the exceptional running economy of East African runners.

Methods:

Seventeen elite long-distance runners (9 Eritrean, 8 European) performed an incremental maximal running test and 3 submaximal running bouts at 17, 19, and 21 km/h. During the tests, gas-exchange parameters were measured to determine maximal oxygen uptake (VO2max) and running economy (RE). In addition, ground-contact time, swing time, stride length, and stride frequency were measured.

Results:

The European runners had higher VO2max values than the Eritrean runners (77.2 ± 5.2 vs 73.5 ± 6.0 mL · kg−1 · min−1, P = .011, effect sizes [ES] = 0.65), although Eritrean runners were more economical at 19 km/h (191.4 ± 10.4 vs 205.9 ± 13.3 mL · kg−1 · min−1, P = .026, ES = 1.21). There were no differences between groups for ground-contact time, swing time, stride length, or stride frequency at any speed. Swing time was associated with running economy at 21 km/h in the Eritrean runners (r = .71, P = .033), but no other significant association was found between RE and biomechanical variables. Finally, best 10-km performance was significantly correlated with RE (r = –.57; P = .013).

Conclusions:

Eritrean runners have superior RE compared with elite European runners. This appears to offset their inferior VO2max. However, the current data suggest that their better RE does not have a biomechanical basis. Other factors, not measured in the current study, may contribute to this RE advantage.

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Sarah Dempster, Rhiannon Britton, Andrew Murray and Ricardo J. S. Costa

The aims of this study were to assess the dietary intake and monitor self-reported recovery quality and clinical symptomology of a male ultra-endurance runner who completed a multiday ultra-endurance running challenge covering 4,254 km from North Scotland to the Moroccan Sahara desert over 78 consecutive days. Food and fluid intakes were recorded and analyzed through dietary analysis software. Body mass (BM) was determined before and after running each day, and before sleep. Clinical symptomology and perceived recovery quality were recorded each day. Whole blood hemoglobin and serum ferritin were determined before and after the challenge. Total daily energy (mean ± SD: 23.2 ± 3.2MJ·day−1) and macronutrient intake (182 ± 31g·day−1 protein, 842 ± 115g·day−1 carbohydrate, 159 ± 55 g·day−1 fat) met consensus nutritional guidelines for endurance performance. Total daily water intake through foods and fluids was 4.8 ± 2.0L·day−1. Water and carbohydrate intake rates during running were 239 ± 143ml·h−1 and 56 ± 19g·h−1, respectively. Immediately after running, carbohydrate and protein intakes were 1.3 ± 1.0g·kg BM−1 and 0.4 ± 0.2g·kg BM−1, respectively. Daily micronutrient intakes ranged from 109 to 662% of UK RNIs. Prerunning BM was generally maintained throughout. Overall exercise-induced BM loss averaged 0.8 ± 1.0%; although BM losses of ≥ 2% occurred in the latter stages, a reflection of the warmer climate. Varying degrees of self-reported perceived recovery quality and clinical symptomology occurred throughout the challenge. This case study highlights oscillations in dietary habits along 78 consecutive days of ultra-endurance running, dependent on changes in ambient conditions and course topography. Nevertheless, nutrition and hydration status were maintained throughout the challenge. Despite dietary iron intake above RNI and iron supplementation, this alone did not prevent deficiency symptoms.

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Mathieu Lacome, Julien Piscione, Jean-Philippe Hager and Christopher Carling

Purpose:

To investigate the patterns and performance of substitutions in 18 international 15-a-side men’s rugby union matches.

Methods:

A semiautomatic computerized time–motion system compiled 750 performance observations for 375 players (422 forwards, 328 backs). Running and technical-performance measures included total distance run, high-intensity running (>18.0 km/h), number of individual ball possessions and passes, percentage of passes completed, and number of attempted and percentage of successful tackles.

Results:

A total of 184 substitutions (85.2%) were attributed to tactical and 32 (14.8%) to injury purposes respectively. The mean period for non-injury-purpose substitutions in backs (17.7%) occurred between 70 and 75 min, while forward substitutions peaked equally between 50–55 and 60–65 min (16.4%). Substitutes generally demonstrated improved running performance compared with both starter players who completed games and players whom they replaced (small differences, ES –0.2 to 0.5) in both forwards and backs over their entire time played. There was also a trend for better running performance in forward and back substitutes over their first 10 min of play compared with the final 10 min for replaced players (small to moderate differences, ES 0.3–0.6). Finally, running performance in both forward and back substitutes was generally lower (ES –0.1 to 0.3, unclear or small differences) over their entire 2nd-half time played compared with their first 10 min of play. The impact of substitutes on technical performance was generally considered unclear.

Conclusions:

This information provides practitioners with practical data relating to the physical and technical contributions of substitutions that subsequently could enable optimization of their impact on match play.

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Graham J. Mytton, David T. Archer, Louise Turner, Sabrina Skorski, Andrew Renfree, Kevin G. Thompson and Alan St Clair Gibson

Purpose:

Previous literature has presented pacing data of groups of competition finalists. The aim of this study was to analyze the pacing patterns displayed by medalists and nonmedalists in international competitive 400-m swimming and 1500-m running finals.

Methods:

Split times were collected from 48 swimming finalists (four 100-m laps) and 60 running finalists (4 laps) in international competitions from 2004 to 2012. Using a cross-sectional design, lap speeds were normalized to whole-race speed and compared to identify variations of pace between groups of medalists and nonmedalists. Lap-speed variations relative to the gold medalist were compared for the whole field.

Results:

In 400-m swimming the medalist group demonstrated greater variation in speed than the nonmedalist group, being relatively faster in the final lap (P < .001; moderate effect) and slower in laps 1 (P = .03; moderate effect) and 2 (P > .001; moderate effect). There were also greater variations of pace in the 1500-m running medalist group than in the nonmedalist group, with a relatively faster final lap (P = .03; moderate effect) and slower second lap (P = .01; small effect). Swimming gold medalists were relatively faster than all other finalists in lap 4 (P = .04), and running gold medalists were relatively faster than the 5th- to 12th-placed athletes in the final lap (P = .02).

Conclusions:

Athletes who win medals in 1500-m running and 400-m swimming competitions show different pacing patterns than nonmedalists. End-spurtspeed increases are greater with medalists, who demonstrate a slower relative speed in the early part of races but a faster speed during the final part of races than nonmedalists.

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Michael J. Ormsbee, Brandon D. Willingham, Tasha Marchant, Teresa L. Binkley, Bonny L. Specker and Matthew D. Vukovich

(Physio-Dyne Instrument Corp., Quogue, NY). The test protocol was modified for each individual by allowing them, with help of a graduate research assistant, to determine a comfortable but challenging running speed for the test. The speed of the treadmill remained constant as the grade increased 2% every 2

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Michael Doherty

The purpose of this study was to evaluate the effect of acute caffeine ingestion on the maximal accumulated oxygen deficit (MAOD) and short-term running performance. Nine well-trained males performed a preliminary assessment and. at least 4 days later, a supramaximal run to exhaustion. Their VO2max values were determined, and the MAOD test at an exercise intensity equivalent to 125% VO2max was performed. Caffeine (5 mg ⋅ kg−1) or placebo was administered 1 hr prior to the MAOD in a double-blind, randomized cross-over study. In comparison to the placebo condition, subjects in the caffeine condition developed a significantly greater MAOD and increased their run lime to exhaustion. However, posl-MAOD blood lactate concentration ([HLa]) was not different between trials for caffeine and placebo. Caffeine ingestion can be an effective ergogenic aid for short-term, supramaximal running performance and can increase MAOD. However, these results do not appear to be related to an increased [HLa).