The aim of this study was to characterise the acceleration and sprint profiles of elite football match play in one Norwegian elite football team (Rosenborg FC). Fifteen professional players in five playing positions took part in the study (n = 101 observations). Player movement was recorded during every domestic home game of one full season (n = 15) by an automatic tracking system based on microwave technology. Each player performed 91 ± 21 accelerations per match, with a lower number in the second compared with the first half (47 ± 12 vs. 44 ± 12). Players in lateral positions accelerated more often compared to players in central positions (98.3 ± 20.5 vs. 85.3 ± 19.5, p
Human pregnancy is associated with increased requirements for dietary energy and this increase may be partly offset by reductions in physical activity during gestation. Studies in well-nourished women have shown that the physical activity level (PAL), obtained as the total energy expenditure (TEE) divided by the BMR, decreases in late pregnancy. However, it is not known if this decrease is really caused by reductions in physical activity or if it is the result of decreases in energy expenditure/BMR (the so-called metabolic equivalent, MET) for many activities in late pregnancy. In the present study activity pattern, TEE and BMR were assessed in twenty-three healthy Swedish women before pregnancy as well as in gestational weeks 14 and 32. Activity pattern was assessed using a questionnaire and heart rate recording. TEE was assessed using the doubly labelled water method and BMR was measured by means of indirect calorimetry. When compared to the pre-pregnant value, there was little change in the PAL in gestational week 14 but it was significantly reduced in gestational week 32. Results obtained by means of the questionnaire and by heart rate recording showed that the activity pattern was largely unaffected by pregnancy. The findings support the following conclusion: in a population of well-nourished women where the activity pattern is maintained during pregnancy, the increase in BMR represents approximately the main part of the pregnancy-induced increase in TEE, at least until gestational week 32.
The aim of this study was to describe the activity profile of top-class female soccer referees during competition and to relate it to the position of the ball. Ten matches from the Fédération Internationale de Football Association (FIFA) under-20 female World Championships held in Russia in 2006 were filmed and the kinematical parameters of the female referees (n=10) and the ball were determined using a two-dimensional photogrammetric video system based on direct linear transformation (DLT) algorithms. Total distance covered during a match was 10 km, of which 1.3 km represented high-intensity activities (>13 km/h). The referees' highest mobility was achieved in the initial 15 min of the match, covering greater distance and performing more intense exercise (P
Hamstring strain is a common injury in sprinters and jumpers, and therefore time to return to sport and secondary prevention become of particular concern.
To compare the effectiveness of two rehabilitation protocols after acute hamstring injury in Swedish elite sprinters and jumpers by evaluating time needed to return to full participation in the training process.
Prospective randomised comparison of two rehabilitation protocols.
Fifty-six Swedish elite sprinters and jumpers with acute hamstring injury, verified by MRI, were randomly assigned to one of two rehabilitation protocols. Twenty-eight athletes were assigned to a protocol emphasising lengthening exercises, L-protocol, and 28 athletes to a protocol consisting of conventional exercises, C-protocol. The outcome measure was the number of days to return to full training. Re-injuries were registered during a period of 12 months after return.
Time to return was significantly shorter for the athletes in the L-protocol, mean 49 days (1SD±26, range 18-107 days), compared with the C-protocol, mean 86 days (1SD±34, range 26-140 days). Irrespective of protocol, hamstring injuries where the proximal free tendon was involved took a significantly longer time to return than injuries that did not involve the free tendon, L-protocol: mean 73 vs 31 days and C-protocol: mean 116 vs 63 days, respectively. Two reinjuries were registered, both in the C-protocol.
A rehabilitation protocol emphasising lengthening type of exercises is more effective than a protocol containing conventional exercises in promoting time to return in Swedish elite sprinters and jumpers.
Norms for the 20-m shuttle run test (with 1 min stages) for the functional and maximal aerobic power (FMAP) are given by age or academic year for boys and girls from 6 to 17 years old for the province of Quebec in May 1981. The sample, 3669 boys and 3355 girls, was selected by stratum according to the scholar population of each region in Quebec. Weight and height for both sexes are similar to those obtained in a recent Canadian study (CAHPER, 1980). The FMAP or the 20-m test results (as a function of age and sex) varies like other published FMAP indices. This supports the validity of the norms of the 20-m test, a test that various advantages in school testing (group testing, progressive protocol and valid test).
The aim of this study was to characterize Kenyan runners in regard to their oxygen uptake and blood and ammonia responses when running. Untrained Kenyan boys (14.2 +/- 0.2 years) and Scandinavian runners were included for comparison. The studies were performed at altitude (approximately 2.000 m.a.s.l.) and, for several Kenyan and Scandinavian runners, at sea level as well. At altitude sedentary adolescent Kenyan boys had a mean maximal oxygen uptake (VO2max) of 47 (44-51) ml.kg-1.min-1, whereas similarly aged boys regularly walking or running but not training for competition reached above 62 (58-71) ml.kg-1.min-1 in VO2max. Kenyan runners in active training had 68 +/- 1.4 ml.kg-1.min-1 at altitude and 79.9 +/- 1.4 ml.kg-1.min-1 at sea level, with individuals reaching 85 ml.kg-1.min-1. The best Scandinavian runners were not significantly different from the Kenyan runners in VO2max both at altitude and at sea level, but none of the Scandinavians reached as high individual values as observed for some Kenyan runners. The running efficiency, determined as the oxygen cost at a given running speed, was less in the Kenyan runners, and the difference became more pronounced when body weight was expressed in ml.kg-0.75 min-1. Blood lactate concentration was in general lower in the Kenyan than in the Scandinavian runners, and the Kenyans also had extremely low ammonia accumulation in the blood even at very high exercise intensities. It is concluded that it is the physical activity during childhood, combined with intense training as teenagers that brings about the high VO2max observed in some Kenyan runners. Their high aerobic capacity, as well as their good running economy, makes them such superior runners. In addition, their low blood lactate and ammonia accumulation in blood when running may also be contributing factors.
Physiological and biochemical profiles of six elite Canadian 800 meter runners are presented. Anthropometric data was recorded. Aerobic capacity was assessed on a treadmill run to fatigue; the initial treadmill velocity was 2.22 m X s-1 increasing by 0.22 m X s-1 each minute. VO2max was determined by the mean of the four highest consecutive 15 second values. The Anaerobic Speed Test (AST) (20 degrees incline, 3.52 m X s-1 to fatigue) was used to assess anaerobic performance characteristics. Two minute post-AST blood samples were analyzed for lactate. Needle biopsies were obtained at rest from the vastus lateralis muscle. The muscle fibers were classified and a homogenate of the muscle was used in the determination of buffering capacity. These are young athletes with a low percentage body fat. The mean VO2max was 63.6 +/- 2.9 ml X kg-1 X min-1. The anaerobic capacity is striking with the mean AST time of 114.3 +/- 16.3 seconds and post-AST lactate values of 22.0 +/- 1.4 mmol X l-1. The skeletal muscle buffering capacity was elevated above normal by 50% indicating an enhanced capability of resisting changes in intracellular pH which may affect performance.
The fitness test for correctional officer applicants (FITCO) was constructed a priori to conform to requirements established by the Meiorin Decision of the Supreme Court of Canada. A critical obligation from this decision is to determine whether the FITCO has the potential of adverse impact on any subpopulation of applicants and, if so, whether it is possible to provide accommodation. The FITCO pass rate was 28.6% for 56 women and 72.7% for 22 men, which indicates adverse impact on the female applicants. There was no specific adverse impact on minority applicants. To evaluate training as accommodation for adverse impact, a subgroup of 40 females and 8 males engaged in a 6-week FITCO-specific training program with pre-FITCO and post-FITCO performance evaluations. Over the 6 weeks, the overall FITCO pass rate of the females improved to 82.5%, whereas the pass rate of the males improved to 100%, indicating that the training program removed the adverse impact that the FITCO had on the females. We conclude that although the FITCO is likely to have an adverse impact on female correctional officer applicants, a 6-week FITCO-specific training program can provide the accommodation necessary to overcome the potential adverse impact, and the FITCO meets all the requirements established by the Supreme Court of Canada's Meiorin Decision.
OBJECTIVE: To assess changes in muscle glycogen (MG) and triglyceride (MT) concentrations in aerobically conditioned sled dogs during prolonged exercise. ANIMALS: 54 Alaskan sled dogs fed a high-fat diet. PROCEDURES: 48 dogs ran 140-km distances on 4 consecutive days (cumulative distance, up to 560 km); 6 dogs remained as nonexercising control animals. Muscle biopsies were performed immediately after running 140, 420, or 560 km (6 dogs each) and subsequently after feeding and 7 hours of rest. Single muscle biopsies were performed during recovery at 28 hours in 7 dogs that completed 560 km and at 50 and 98 hours in 7 and 6 dogs that completed 510 km, respectively. Tissue samples were analyzed for MG and MT concentrations. RESULTS: In control dogs, mean +/- SD MG and MT concentrations were 375 +/- 37 mmol/kg of dry weight (kgDW) and 25.9 +/- 10.3 mmol/kgDW, respectively. Compared with control values, MG concentration was lower after dogs completed 140 and 420 km (137 +/- 36 mmol/kgDW and 203 +/- 30 mmol/kgDW, respectively); MT concentration was lower after dogs completed 140, 420, and 560 km (7.4 +/- 5.4 mmol/kgDW; 9.6 +/- 6.9 mmol/kgDW, and 6.3 +/- 4.9 mmol/kgDW, respectively). Depletion rates during the first run exceeded rates during the final run. Replenishment rates during recovery periods were not different, regardless of distance; only MG concentration at 50 hours was significantly greater than the control value. CONCLUSIONS AND CLINICAL RELEVANCE: Concentration of MG progressively increased in sled dogs undergoing prolonged exercise as a result of attenuated depletion.