Search results for "athlete"
showing 10 items of 777 documents
Differences in mechanical efficiency between power- and endurance-trained athletes while jumping
1995
Mechanical efficiency (ME) of jumping exercises was compared between power-trained (n = 11) and endurance-trained athletes (n = 10) using both a biomechanical and a physiological approach. In drop jumps and in stretch-shortening cycle exercise on a special sledge (sledge jumps), the subjects performed 60 muscle actions from a dropping height of optimum minus 40 cm (O − 40), as well as from dropping heights of optimum (O) and optimum plus 40 cm (O + 40). Thus, they were tested in six different tests which lasted for a total of 3 min for each. The mean ME values in the drop jumps from the lowest dropping height upwards were as follows: 23.8 (SD 5.3)%, 35.5 (SD 10.8)% and 39.2 (SD 6.6)% for th…
Effects of acute exercise and xanthine oxidase inhibition on novel cardiovascular biomarkers.
2013
Several sports have been associated with a postexercise increase of cardiac, liver, and skeletal muscle biomarkers of injury. Exhaustive or acute physical exercise causes an increased generation of reactive oxygen species, resulting in cellular injury. Thus, exercise and training may trigger pathophysiological changes in serum concentrations of a variety of biomarkers. In this study, we aimed to evaluate the variation of novel biomarkers of stress and cardiovascular disease such as copeptin, midregional part of proadrenomedullin (MR-proADM), growth differentiation factor 15 (GDF15), soluble vascular endothelial growth factor receptor, and placental growth factor along with uric acid before …
High-density electromyography activity in various hamstring exercises
2019
Proximal-distal differences in muscle activity are rarely considered when defining the activity level of hamstring muscles. The aim of this study was to determine the inter-muscular and proximal-distal electromyography (EMG) activity patterns of hamstring muscles during common hamstring exercises. Nineteen amateur athletes without a history of hamstring injury performed 9 exercises, while EMG activity was recorded along the biceps femoris long head (BFlh) and semitendinosus (ST) muscles using 15-channel high-density electromyography (HD-EMG) electrodes. EMG activity levels normalized to those of a maximal voluntary isometric contraction (%MVIC) were determined for the eccentric and concentr…
Use of Visual Feedback During Jump-Squat Training Aids Improvement in Sport-Specific Tests in Athletes.
2020
Vanderka, M, Bezak, A, Longova, K, Krcmar, M, and Walker, S. Use of visual feedback during jump-squat training aids improvement in sport-specific tests in athletes. J Strength Cond Res 34(8): 2250-2257, 2020-This study investigated the effects of instantaneous performance feedback during the jump-squat exercise over a 6-week training period. Twenty-five strength-trained athletes were randomly divided into an instant feedback (n = 13, half-squat 3-repetition maximum (3RM)/body mass = 2.38 ± 0.19) or a nonfeedback (n = 12, half-squat 3RM/body mass = 2.03 ± 0.44) group. Both groups performed the same training program (3 × week), consisting of 4 sets of 8 repetitions (weeks 1-3) and 8 sets of 4…
Lipid peroxidation and total antioxidant status in unprofessional athletes before and after a cardiopulmonary test.
2009
We examined lipid peroxidation, expressed as thiobarbituric acid-reactive substances (TBARS) and total antioxidant status (TAS) before and after a cardiopulmonary test, in 20 sedentary controls and in 62 unprofessional male athletes subdivided into 3 subgroups. The first included subjects who practised endurance sports (14 cyclists and 9 endurance swimmers), the second subjects who practised mixed sports (6 basket players, 6 judoists, 8 water polo players) and the third group subjects who practised power sports (3 sprint runners, 4 weightlifters, 12 sprint swimmers). In the whole group of athletes an increase in TBARS and a decrease in TAS were present at baseline. Subdividing the whole gro…
Effects of barbell back squat stance width on sagittal and frontal hip and knee kinetics
2018
Different stance widths are commonly utilized when completing the barbell back squat during athletic general preparedness training. Width manipulation is thought to influence sagittal plane stimuli to the hip and knee extensors, the primary extensor musculature in the squat. However, how width manipulation affects frontal plane stimuli is less understood. Knowledge of hip and knee net joint moments (NJM) could improve exercise selection when aiming to improve sport-specific performance and prevent injuries. Fourteen adult amateur rugby athletes were recruited for this study. After a familiarization period, participants performed wide- (WIDE, 1.5× greater trochanter width) and narrow-stance …
Bone Mineral Density and Long Term Exercise
1993
Evidence in human studies of the association of long term habitual exercise with bone mineral content (BMC) and density (BMD) largely comes from studies in athletes. In young adults, the highest BMC and BMD values have been found in strength and power-trained athletes, while endurance activities such as long distance running and swimming seem less effective with regard to peak bone density. Intensive endurance training may even be associated with amenorrhoea and decreased trabecular bone density in young females. However, after menopause female athletes show greater bone mass indicating that they do not share the accelerated decline in BMC observed in a nonathletic population. Middle-aged a…
Some biomechanical aspects of the foot and ankle in athletes with and without shin splints
1983
Thirteen adult male athletes (long-distance runners and orienteerers without foot problems) and 35 male ath letes with shin splints were compared with respect to: 1) the position of the lower leg and the heel while standing, 2) the passive range of mobility in the subtalar joint, and 3) the angular displacement between the calcaneus and the midline of the lower leg (Achilles tendon angle) while running with bare feet on a tread mill. In standing, the two groups differed statistically significantly in the Achilles tendon angle, which values were greater in the shin splint group. With respect to passive mobility, the athletes with shin splints had significantly greater (P < 0.05-0.01) ang…
Training at maximal power in resisted sprinting: Optimal load determination methodology and pilot results in team sport athletes.
2018
Aims: In the current study we investigated the effects of resisted sprint training on sprinting performance and underlying mechanical parameters (force-velocity-power profile) based on two different training protocols: (i) loads that represented maximum power output (Lopt) and a 50% decrease in maximum unresisted sprinting velocity and (ii) lighter loads that represented a 10% decrease in maximum unresisted sprinting velocity, as drawn from previous research (L10). Methods: Soccer [n = 15 male] and rugby [n = 21; 9 male and 12 female] club-level athletes were individually assessed for horizontal force-velocity and load-velocity profiles using a battery of resisted sprints, sled or robotic r…
Do elite endurance athletes report their training accurately?
2013
Purpose:The purpose of this study was to validate the accuracy of self-reported (SR) training duration and intensity distribution in elite endurance athletes.Methods:Twenty-four elite cross-country skiers (25 ± 4 y, 67.9 ± 9.88 kg, 75.9 ± 6.50 mL · min−1 · kg−1) SR all training sessions during an ~14-d altitude-training camp. Heart rate (HR) and some blood lactate measurements were collected during 466 training sessions. SR training was compared with recorded training duration from HR monitors, and SR intensity distribution was compared with expert analysis (EA) of all session data.Results:SR training was nearly perfectly correlated with recorded training duration (r = .99), but SR training…