Purpose: To test the effectiveness of sitting surfaces with varied amounts of stability on muscle activity and energy expenditure.Methods: Using a within-participants repeated measures design, 11 healthy young-adult f...Purpose: To test the effectiveness of sitting surfaces with varied amounts of stability on muscle activity and energy expenditure.Methods: Using a within-participants repeated measures design, 11 healthy young-adult females(age = 20.0 ± 1.8 years) were measured using indirect calorimetry to assess energy expenditure, and electromyography to assess muscular activation in trunk and leg musculature under 3different sitting surfaces: flat-firm surface, air-filled cushion, and a stability ball. Data were analyzed using repeated measures analysis of variance with follow-up pairwise contrasts used to determine the specific effects of sitting surface on muscle activation and energy expenditure.Results: Significantly greater energy expenditure was recorded for the stability ball(p = 0.01) and the cushion(p = 0.03) over the flat surface(10.4% and 9.6% greater, respectively), with no differences between the ball and the cushion. Both the ball and the cushion produced higher tibialis anterior activation over the flat surface(1.09 and 0.63 root-mean-square millivolts(RMSmv), respectively), while the stability ball produced higher soleus activity over both cushion and flat surfaces(3.97 and 4.24 RMSmv, respectively). Additionally, the cushion elicited higher adductor longus activity over the ball and flat surfaces(1.76 and 1.81 RMSmv, respectively), but no trunk musculature differences were revealed.Conclusion: Compliant surfaces resulted in higher levels of muscular activation in the lower extremities facilitating increased caloric expenditure.Given the increasing trends in sedentary careers and the increases in obesity, this is an important finding to validate the merits of active sitting facilitating increased caloric expenditure and muscle activation.展开更多
通过不同的无氧阈检测方法检测无氧阈指标出现的时间顺序,并对出现无氧阈时各相关指标进行相关性分析,以探讨不同无氧阈之间的关系。让8名赛艇运动员在ConceptⅡ风轮式赛艇测功仪上进行递增负荷测试,每级负荷3 min,直至力竭,同时测试每...通过不同的无氧阈检测方法检测无氧阈指标出现的时间顺序,并对出现无氧阈时各相关指标进行相关性分析,以探讨不同无氧阈之间的关系。让8名赛艇运动员在ConceptⅡ风轮式赛艇测功仪上进行递增负荷测试,每级负荷3 min,直至力竭,同时测试每级负荷后的血乳酸,全程记录肌电以及气体代谢量,并做相关分析。结果表明:1)肌电阈、通气阈和乳酸阈3种无氧阈指标出现的时间依次为8 min 58 s、9 min 22 s和9 min 48 s;2)肌电阈、通气阈和乳酸阈依次出现的时间差均不超过30 s,并且通气阈和乳酸阈之间无显著性差异(P>0.05)。3种无氧阈依次出现的原因是快肌纤维的快速动员引起了乳酸急剧增加,进而在转运到血液中时首先引起酸碱缓冲对的中和,当强度进一步增加时,产生的乳酸大大超过了乳酸的清除能力,进而引起血乳酸急剧增加。展开更多
文摘Purpose: To test the effectiveness of sitting surfaces with varied amounts of stability on muscle activity and energy expenditure.Methods: Using a within-participants repeated measures design, 11 healthy young-adult females(age = 20.0 ± 1.8 years) were measured using indirect calorimetry to assess energy expenditure, and electromyography to assess muscular activation in trunk and leg musculature under 3different sitting surfaces: flat-firm surface, air-filled cushion, and a stability ball. Data were analyzed using repeated measures analysis of variance with follow-up pairwise contrasts used to determine the specific effects of sitting surface on muscle activation and energy expenditure.Results: Significantly greater energy expenditure was recorded for the stability ball(p = 0.01) and the cushion(p = 0.03) over the flat surface(10.4% and 9.6% greater, respectively), with no differences between the ball and the cushion. Both the ball and the cushion produced higher tibialis anterior activation over the flat surface(1.09 and 0.63 root-mean-square millivolts(RMSmv), respectively), while the stability ball produced higher soleus activity over both cushion and flat surfaces(3.97 and 4.24 RMSmv, respectively). Additionally, the cushion elicited higher adductor longus activity over the ball and flat surfaces(1.76 and 1.81 RMSmv, respectively), but no trunk musculature differences were revealed.Conclusion: Compliant surfaces resulted in higher levels of muscular activation in the lower extremities facilitating increased caloric expenditure.Given the increasing trends in sedentary careers and the increases in obesity, this is an important finding to validate the merits of active sitting facilitating increased caloric expenditure and muscle activation.
文摘通过不同的无氧阈检测方法检测无氧阈指标出现的时间顺序,并对出现无氧阈时各相关指标进行相关性分析,以探讨不同无氧阈之间的关系。让8名赛艇运动员在ConceptⅡ风轮式赛艇测功仪上进行递增负荷测试,每级负荷3 min,直至力竭,同时测试每级负荷后的血乳酸,全程记录肌电以及气体代谢量,并做相关分析。结果表明:1)肌电阈、通气阈和乳酸阈3种无氧阈指标出现的时间依次为8 min 58 s、9 min 22 s和9 min 48 s;2)肌电阈、通气阈和乳酸阈依次出现的时间差均不超过30 s,并且通气阈和乳酸阈之间无显著性差异(P>0.05)。3种无氧阈依次出现的原因是快肌纤维的快速动员引起了乳酸急剧增加,进而在转运到血液中时首先引起酸碱缓冲对的中和,当强度进一步增加时,产生的乳酸大大超过了乳酸的清除能力,进而引起血乳酸急剧增加。
