Search results for "ground"
showing 10 items of 2432 documents
An experimental controlled study on postural sway and therapeutic exercise in subjects with low back pain.
2000
Objectives: To describe postural sway and its associations to background factors, low back pain and functional capacity. To evaluate the changes in postural sway after three months of therapeutic exercise in the gym or at home. Design: A one-year randomized experimental trial evaluated postural sway in three study groups: intensive training, home exercise and control group. Setting: Subjects were recruited from seven local occupational health care centres in Central Finland and were examined at Central Finland Hospital by medical doctors. Measurements and therapeutic exercise programmes were carried out in the Research Laboratory of Sport and Health Sciences at Jyväskylä University. Subjec…
Bone Density, Structure and Strength, and Their Determinants in Aging Sprint Athletes
2012
This study was undertaken to examine bone properties in masters sprinters of different ages and younger reference subjects. In addition, the association of sport-specific ground reaction force, muscle, training, and hormone characteristics with the bone parameters was evaluated in the athletes.Bone densitometric, structural, and strength parameters were assessed by peripheral quantitative computed tomography at the distal and midtibia in 83 male sprinters (40-85 yr) and 19 physically active referents (31-45 yr). Between-group differences were analyzed by ANCOVA with body mass and height as covariates.Bone values were generally greater in athletes than referents, the greatest differences bei…
Biomechanical loading in the triple jump
2000
The triple jump is a demanding field event in which a jumper must tolerate extremely high impact forces while maintaining high horizontal speed. The present study was designed to clarify the mechanical loading characteristics and the role of neuromuscular function in the triple jump. Seven national triple jumpers (4 males, 3 females) volunteered to perform 3-6 jumps. The mean best performances were 14.32+/-0.45 m and 11.90+/-0.28 m for males and females, respectively. The three longest triple jumps for each jumper were selected for final analysis. The mean contact times were 0.139 s (hop), 0.157 s (step) and 0.177 s (jump). The largest ground reaction forces were observed in the step (15.2 …
Uptake of permethrin from impregnated clothing.
2010
In order to examine exposure and health risks which can arise from permethrin-impregnated clothing, a controlled trial was conducted. In a study group consisting of 187 volunteers in total, a subgroup of 86 persons was equipped with permethrin-impregnated battle dress uniforms (BDU) for 28 days. One hundred and one persons served as a control group, wearing non-impregnated BDUs throughout the entire study period of 56 days. Internal exposure of all participants was assessed by determination of urinary permethrin metabolites (cis-DCCA, trans-DCCA and 3-PBA) on day 0, 14 and 28 of the wearing period and 28 days after termination of wearing. Exposure levels in the control group ranged within b…
Effects of muscle – tendon length on joint moment and power during sprint starts
2005
The aim of this study was to examine the effects of muscle-tendon length on joint moment and power during maximal sprint starts. Nine male sprinters performed maximal sprint starts from the blocks that were adjusted either to 40 degrees or 65 degrees to the horizontal. Ground reaction forces were recorded at 833 Hz using a force platform and kinematic data were recorded at 200 Hz with a film camera. Joint moments and powers were analysed using kinematic and kinetic data. Muscle - tendon lengths of the medial gastrocnemius, soleus, vastus medialis, rectus femoris and biceps femoris were calculated from the set position to the end of the first single leg contact. The results indicated that bl…
Medial gastrocnemius muscle behavior during human running and walking.
2007
Utilization of elastic energy in the tendinous tissues (TT) of the human skeletal muscle may be task dependent. The present study was designed to investigate this problem by comparing the fascicle-TT interaction of the medial gastrocnemius muscle (MG) during ground contact of running and walking. Seven subjects ran and walked with a natural cadence. Ankle and knee joint angular data were recorded by electrogoniometers for estimating the entire MG muscle-tendon unit (MTU) length, together with the ground reaction forces. The MG fascicle length was measured by using the high-speed ultrasound image scanning during movements. The results showed that in running, after the rapid early fascicle st…
General practitioners’ relationship with preventive knowledge: a qualitative study
2014
General practitioners (GPs) do not provide enough preventive care. Nonetheless, without a detailed understanding of the logical processes that underlie their practices, it remains difficult to develop effective means of improvement. Their relationship to knowledge is one of three elements that strongly structure GPs’ preventive work (together with the doctor–patient relationship and the organisation of their professional space).The objective of this article was to explore the question of GPs’ relationship to knowledge about prevention. In 2010–2011, semi-directive interviews with a diverse sample of 100 GPs practising in the Paris metropolitan area were conducted. These interviews were cod…
One-year persistence of individual gait patterns identified in a follow-up study – A call for individualised diagnose and therapy
2017
Abstract Although a hunch about the individuality of human movements generally exists, differences in gait patterns between individuals are often neglected. To date, only a few studies distinguished individual gait patterns in terms of uniqueness and emphasised the relevance of individualised diagnoses and therapy. However, small sample sizes have been a limitation on identifying subjects based on gait patterns, and little is known about the permanence of subject-specific characteristics over time. The purpose of this study was (1) to prove the uniqueness of individual gait patterns within a larger sample and (2) to prove the long-term permanence of individual gait patterns. A sample of 128…
Potentiation of the mechanical behavior of the human skeletal muscle through prestretching
1979
Force-velocity and power-velocity curves in a vertical jump involving movements around several joints were derived from vertical ground reaction forces and knee angular velocities. The jumps were performed with weights from 10 to 160 kg added on the shoulders. The obtained curves from a semi-squatting static starting position resembled those reported for isolated muscles or single muscle groups. Vertical jumps were also performed in the conditions where the shortening of the leg extensors was preceded by prestretching of the active muscles either through a preparatory counter-movement or dropping down on the force-platform from the various heights ranging from 20 to 100 cm. Prestretching mo…
Bipedal distribution of human vestibular‐evoked postural responses during asymmetrical standing
2002
Galvanic vestibular stimulation (GVS) evokes responses in muscles of both legs when bilateral stimuli are applied during normal stance. We have used this technique to assess whether asymmetrical standing alters the distribution of responses in the two legs. Subjects stood either asymmetrically with 75% of their body weight on one leg or symmetrically with each leg taking 50% of their body weight. The net response in each leg was taken from changes in ground reaction force measured from separate force plates under each foot. The net force profile consisted of a small initial force change that peaked at approximately 200 ms followed by an oppositely directed larger component that peaked at ap…