应用三轴加速度计数评价功率车骑行下肢稳定性

Application of Triaxial Accelerometer to Evaluate Bicycle Ergometer Riding Stability of Lower Limb

目的:分别建立室内功率自行车踏频递增骑行和一次力竭骑行2种运动模式,探讨Actigraph GT3X+加速度计3个轴向上的加速度计数变化评价自行车运动员不同强度骑行状态下下肢骑行稳定性的有效性。方法:青年男性自行车运动员等分入优秀组(EG)和普通组(NG)。2组运动员在1周内分别进行Wattbike功率自行车递增运动负荷骑行测试(GXT)和模拟1 km计时骑行测试(1 kmTT),2次测试间隔72 h。测试中分别在运动员的右腿腓骨头下缘和外踝上缘固定1个Actigraph GT3X+三轴加速度计,测量膝、踝关节在矢状轴(SA)、冠状轴(CA)和垂直轴(VA)方向上的加速度计数。结果:(1)GXT中,2组运动员膝、踝关节3个轴向的加速度计数均表现为VA>SA>CA,并随着骑行频率的提高而有所增加;2组运动员膝、踝关节VA轴向加速度计数均与骑行功率显著相关(r>0.9),仅NG组膝关节CA计数与功率存在中度相关关系(0.7<r<0.8,P<0.01);而NG组完成6级骑行的CA计数均显著高于EG组(P<0.05)。(2)1 kmTT中,EG组平均功率和平均频率分别较NG组高25.4%和9.2%(P<0.05);NG组膝关节VA计数与功率呈中度相关(0.7<r<0.8,P<0.01),而EG组膝关节的CA轴向计数较NG组低19.7%(P<0.05);2组运动员踝关节VA和SA轴计数与功率均表现出高度相关性(r>0.8,P<0.01),但组间未见明显差异。结论:膝、踝关节的CA加速度计数变化可有效评价下肢运动环节的骑行稳定性,CA计数增加提示下肢稳定性降低。膝关节SA加速度计数是反映运动员踏蹬过程中是否有主动抬腿上提、促进踏蹬圆滑的有效指标。

Purposes:This paper discussed the changes of numbers on three axial directions of Actigraph GT3X+accelerometer and then evaluated the validity of lower limb stability of cyclists during riding under different riding states,setting two motor patterns,riding with progressively increased cadence of indoor bicycle ergometer and one riding with exhaustion.Methods:Youth male cyclists were divided into elite group(EG)and normal group(NG)equally.2 groups of cyclists were conducted Wattbike bicycle ergometer graded Exercise testing(GXT)and simulated 1km time-trial(1kmTT)in one week.The time interval was 72 hours between 2 tests.Two Actigraph GT3X+Triaxial Accelerometers were fixed respectively at the inferior margin of right fibula and superior margin of lat eral malleolus of athlete separately in the test.The Acceleration counts of knee and ankle in sagittal axis(SA),coronal axis(CA)and vertical axis(VA)were measured.Results:(1)The acceleration counts of knee and ankle in three axial directions of 2 groups presented as VA>SA>CA in GXT and also increased with the pedaling cadence increasing.There was a significant correlation between acceleration counts of knee and ankle in VA and riding power(r>0.9).However,there was moderate correlation between the acceleration counts of kneel in CA and power only in NG(0.7<r<0.8,P<0.01).The acceleration counts in CA completing six graded riding in NG were significantly higher than those in EG(P<0.05).(2)The average power and average cadence in EG in 1kmTT were higher than those in NG by 25.4%and 9.2%(P<0.05).There was moderate correlation between the acceleration counts of kneel in VA and power(0.7<r<0.8,P<0.01).However,the acceleration counts of kneel in CA in EG were lower than those in NG by 19.7%(P<0.05).The acceleration counts of ankle in VA and SA of 2 groups were highly correlated with power(r>0.8,P<0.01),without significant difference between two groups.Conclusions:The changes of acceleration counts of knee and ankle in coronal axis(CA)could evaluate riding stability of lower limb effectively.The increase of coronal axis counts means the decline of riding stability of lower limb.The acceleration counts of knee in sagittal axis(SA)is the effective index to reflect if lower limb has the active pull movement during riding and improve the pedaling smooth.