- ترتیب محصولات: پیش فرض
Advances in the application of information technology to sport performance0 تومان
This paper overviews the diverse information technologies that are used to provide athletes with relevant feedback. Examples taken from various sports are used to illustrate selected applications of technology-based feedback. Several feedback systems are discussed, including vision, audition and proprioception. Each technology described here is based on the assumption that feedback would eventually enhance skill acquisition and sport performance and, as such, its usefulness to athletes and coaches in training is critically evaluated.
Aging, Functional Capacity and Eccentric Exercise Training0 تومان
Aging is a multi-factorial process that ultimately induces a decline in our physiological functioning, causing a decreased health-span, quality of life and independence for older adults. Exercise participation is seen as a way to reduce the impact of aging through maintenance of physiological parameters. Eccentric exercise is a model that can be employed with older adults, due to the muscle’s ability to combine high muscle force production with a low energy cost. There may however be a risk of muscle damage before the muscle is able to adapt. The first part of this review describes the process of aging and how it reduces aerobic capacity, muscle strength and therefore functional mobility. The second part highlights eccentric exercise and the associated muscle damage, in addition to the repeated bout effect. The final section reviews eccentric exercise interventions that have been completed by older adults with a focus on the changes in functional mobility. In conclusion, eccentric endurance exercise is a potential training modality that can be applied to older adults for improving muscle strength, aerobic capacity and functional ability. However, further research is needed to assess the effects on aerobic capacity and the ideal prescription for eccentric endurance exercise.
An accelerometer-based earpiece to monitor and quantify physical activity0 تومان
Background—Physical activity is important in ill-health. Inexpensive, accurate and precise devices could help assess daily activity. We integrated novel activity-sensing technology into an earpiece used with portable music-players and phones; the physical-activity-sensing-earpiece (PASE). Here we examined whether the PASE could accurately and precisely detect physical activity and measure its intensity and thence predict energy expenditure. Methods—Experiment 1: 18 subjects wore PASE with different body postures and during graded walking. Energy expenditure was measured using indirect calorimetry. Experiment 2: Eight subjects wore the earpiece and walked a known distance. Experiment 3: Eight subjects wore the earpiece and ‘jogged’ at 3.5mph. Results—The earpiece correctly distinguished lying from sitting/standing and distinguished standing still from walking (76/76 cases). PASE output showed excellent sequential increases with increased in walking velocity and energy expenditure (r2>0.9). The PASE prediction of free-living walking velocity was, 2.5 ± (SD) 0.18 mph c.f. actual velocity, 2.5 ± 0.16 mph. The earpiece successfully distinguished walking at 3.5 mph from ‘jogging’ at the same velocity (p<0.001). Conclusions—The subjects tolerated the earpiece well and were comfortable wearing it. The PASE can therefore be used to reliably monitor free-living physical activity and its associated energy expenditure.
Effects of Exercise Training on Outcomes in Women With Heart Failure0 تومان
The authors hypothesized that the women enrolled in the HF-ACTION (Heart Failure–A Controlled Trial Investigating Outcomes of Exercise TraiNing) trial and randomly assigned to exercise training (ET) would improve functional capacity as measured by peak oxygen uptake (VO2) compared with those in the usual care group. Furthermore, they hypothesized that the improvement in peak VO2 would correlate with prognosis. They explored whether exercise had a differential effect on outcomes in women versus men. Background There is less evidence for the benefit of ET in women with heart failure (HF) compared with men because of the small numbers of women studied. Methods HF-ACTION was a randomized trial of ET versus usual care in 2,331 patients with class II-IV HF and a left ventricular ejection fraction of 35%. Sex differences in the effects of randomized treatment on clinical outcomes were assessed through the use of a series of Cox proportional hazards models, controlling for covariates known to affect prognosis in HF-ACTION. Results Women had lower baseline peak VO2 and 6-min walk distance than did men (median, 13.4 vs. 14.9 ml/min/kg and 353 vs. 378 m, respectively). An increase in peak VO2 at 3 months was present in women and men in the ET group (mean SD; median, 0.88 2.2, 0.80 and 0.77 2.7, 0.60, respectively, women vs. men; p ¼ 0.42). Women randomly assigned to ET had a significant reduction in the primary endpoint, (hazard ratio: 0.74) compared with men (hazard ratio: 0.99) randomly assigned to ET, with a significant treatment-by-sex interaction (p ¼ 0.027).
EMG amplitude and frequency parameters of muscular activity: Effect of resistance training based on electromyographic fatigue threshold0 تومان
The present study aimed to evaluate the effect of a resistance training program based on the electromyographic fatigue threshold (EMGFT, defined as the highest exercise intensity performed without EMG alterations), on the EMG amplitude (root mean square, RMS) and frequency (median frequency, MF) values for biceps brachii (BB), brachioradialis (BR), triceps brachii (TB) and multifidus (MT). Twenty healthy male subjects, (training group [TG], n = 10; control group [CG], n = 10), firstly performed isometric contractions, and after this, dynamic biceps curl at four different loads to determine the EMGFT. The TG training program used the BB EMGFT value (8 weeks, 2 sessions/week, 3 exhaustive bouts/session, 2 min rest between bouts). No significant differences were found for the isometric force after the training. The linear regression slopes of the RMS with time during the biceps curl presented significant decrease after training for the BB, BR and TB muscles. For the MT muscle, the slope and MF intercept values changed with training. The training program based on the EMGFT influenced EMG the amplitude more than EMG frequency, possibly related to the recruitment patterns of the muscles, although the trunk extensor muscles presented changes in the frequency parameter, showing adaptation to the training program.