This study assessed the effects of exposure to cold (-14 and -9 °C), cool (-4 and 1 °C) and moderate warm (10 and 20 °C) environments on aerobic endurance performance-related variables: maximal oxygen consumption (VO(2max)), running time to exhaustion (TTE), running economy and running speed at lactate threshold (LT). Nine male endurance athletes wearing cross-country ski racing suit performed a standard running test at six ambient temperatures in a climatic chamber with a wind speed of 5 m s(-1). The exercise protocol consisted of a 10-min warm-up period followed by four submaximal periods of 5 min at increasing intensities between 67 and 91 % of VO(2max) and finally a maximal test to exhaustion. During the time course mean skin temperature decreased significantly with reduced ambient temperatures whereas T (re) increased during all conditions. T (re) was lower at -14 °C than at -9 and 20 °C. Running economy was significantly reduced in warm compared to cool environments and was also reduced at 20 °C compared to -9 °C. Running speed at LT was significantly higher at -4 °C than at -9, 10 and 20 °C. TTE was significantly longer at -4 and 1 °C than at -14, 10 and 20 °C. No significant differences in VO(2max) were found between the various ambient conditions. The optimal aerobic endurance performance wearing a cross-country ski racing suit was found to be -4 and 1 °C, while performance was reduced under moderate warm (10 and 20 °C) and cold (-14 and -9 °C) ambient conditions.
Peripheral arterial disease (PAD) patients suffer from reduced blood flow to the lower extremities, which causes impaired walking ability. Plantar flexion (PF) endurance training and maximal strength training (MST) induce distinct types of improvements in walking ability in PAD. However, the combined effects of both exercises are still not explored in these patients. This study examined whether concurrent MST and PF training would induce similar training responses as each training mode alone. Ten patients with PAD underwent 8 weeks of concurrent leg press MST and PF training, three times a week. The reference group (n=10) received recommended exercise guidelines. The training group improved treadmill peak oxygen consumption and incremental protocol time to exhaustion with 12.7 ± 7.7% and 12.6 ± 13.2%. Leg press maximal strength and rate of force development improved with 38.3 ± 3.1% and 140.1 ± 40.3%, respectively, along with a 5.2 ± 6.2% within group work economy improvement. No changes appeared in the reference group. Compared with previous studies, concurrent MST and PF training appear to induce similar training responses in PAD patients as when each training mode is executed alone, and without any adverse effects.
This study investigated if initial calf muscle training immediately followed by whole body training improved aerobic power and cardiovascular function in peripheral arterial disease (PAD) patients. The training group (n = 10) pursued 8 weeks of high aerobic intensity plantar flexion interval training continued by 8 weeks of high aerobic intensity treadmill training. The control group (n = 11) received advice according to exercise guidelines. Treadmill VO2peak and time to exhaustion increased significantly with 16.8 and 23.4% during the plantar flexion training period while no changes occurred in heart stroke volume (SV). Following treadmill training, SV increased with 25.1% while treadmill VO2peak and time to exhaustion increased 9.9 and 16.1%. Plantar flexion training was effective for increasing treadmill VO2peak and time to exhaustion in PAD patients and amplified the effects of the additional treadmill training, as SV increased and treadmill VO2peak and time to exhaustion improved further. This study suggests that calf muscle training prime PAD patients for cardiovascular adaptations when applying whole body exercise.
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