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场地自行车运动员踏蹬动作肌电研究 总被引：1，自引：0，他引：1
为从神经肌肉协调角度研究场地自行车运动员踏蹬动作技术特征,本文结合场地4km专项特点,研究10名场地自行车运动员在500w负荷下以100rpm、120rpm、130rpm、140rpm四种频率稳态骑行时下肢7块肌肉的EMG信号及四组单、双关节拮抗肌协调的变化规律。结果表明,更高踏蹬频率下RF活动显著提前至上提末段,TDC处平滑过渡另有机制。VL和GAS活动区域显著增大。TA突出表现为双峰模式,前峰在协调GAS传递能量和防止VM功能加强引起的膝关节过伸方面起重要作用。更高频率下RF与GM间拮抗机制表现为相反改变,BF/VL始终保持正相关,有助于下踏阶段膝-髋间的净能量传递。VL与GAS间显著负相关保证了近端环节至曲柄的高效传递,TA与GAS间显著负相关侧面证实TA双峰的重要意义。研究提示,专项频率(130-140rpm)下踏蹬动作有其特征的肌肉协调变化。 相似文献
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目的：对场地自行车不同传动比下大强度骑行过程中功率、频率变化进行测评,分析传统疲劳指数、频率指数和净疲劳指数在疲劳评价中的应用价值。方法：10名男子短距离自行车运动员分别使用50：12和50：13两种传动比进行两次200m俯冲骑行测试,使用SRM自行车专用功率记录仪采集骑行全程的功率和踏蹬频率,分别计算传统疲劳指数、频率指数和净疲劳指数。结果：运动员完成200m俯冲骑行到达终点前30s过程中,功率、频率前7s同时逐渐增加,8-11s功率增加但频率维持原来水平,功率在12-15s左右达到最大,此时频率约为130rpm左右,随后可见频率仍在增加,但功率逐步降低。场地自行车大坡俯冲骑行过程中,传统疲劳指数明显高于净疲劳指数,两者计算结果的差异来自与是否将频率变化包括在内。结论：净疲劳指数较传统疲劳指数更好地反映了场地自行车骑行中的功率-频率关系,并能描述不同速度下的疲劳程度。运动员可以通过适度增加传动比,降低频率来提高200m计时赛运动成绩。 相似文献
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本文对自行车运动员在骑行过程中的踏蹬动作进行了研究。测试中使用了肌电、测力和高速摄影同步采集系统。结果表明,测试对象在骑行技术上存在着踝关节力量不足和膝关节主动屈曲不够等问题。文章提出了解决上述问题的途径。 相似文献
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文章从力学的角度和形态学方面,对自行车踏蹬一周中的受力情况,选取六个点(6个角度)的踏蹬技术特征,来进行分析研究,以帮助运动员形成正确的踏蹬骑行动作。 相似文献
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1 问题的提出 自行车运动,就下肢动作而言,是一种非匀速,逆时针进行,两足处以相对立方向的圆周运动。 踏蹬动作是整个下肢动作的关键,合理的踏蹬技术动作可使运动员以最小的能量消耗祈取最佳的工作效率,达到高速度行进。 合理的踏蹬动作是指下肢肌肉协调的交替收缩 相似文献
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在自行车运动中,踏蹬技术对运动成绩的提高起着较大的作用。所以运动员在进行身体高强度训练的同时,必须特别注意提高踏蹬技术,以便尽快提高运动成绩。一般来说,合理的踏蹬技术,在于掌握踏下脚蹬时肌肉紧张的时刻和脚蹬回转时肌肉松弛的时 相似文献
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对女子短距离自行车运动员45 s全力冲刺骑行进行下肢运动学分析,探讨不同水平运动员速度能力的特点,筛选可评价下肢踏蹬技术的运动学指标。使用三维红外运动捕捉系统及SRM自行车测功仪,采集上海自行车队4名女子短距离运动员场地车滚筒练习台上45 s全力冲刺骑行中的下肢运动学参数和踏频。结果表明,钟××速度能力较好,45 s全力冲刺骑行各阶段平均速度较高,但下肢踏蹬"圆滑度"还需进一步提高;顾××和姚××后程速度下降明显,速度耐力明显不足。在全力冲刺骑行后期,运动水平较高的运动员（钟××）踝关节活动度下降明显小于运动水平较低的运动员（顾××和姚××）,提示踝关节活动度下降是影响自行车短距离项目运动员速度耐力的因素之一。 相似文献
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通过实验测试方法,对优秀中长距离自行车运动员进行功率车测试及肌电研究,了解运动员在原地起动阶段的踏频及功率变化情况,以及在原地起动阶段和固定功率车进行踏蹬时．下肢各主要肌肉的激活时间与用力情况,以便掌握运动员骑行过程中主要的用力肌肉,加强训练的针对性和有效性。研究发现,股内侧肌和股外侧肌肌电信号表现明显,提示这两块肌肉可能为踏蹬主要发力肌肉。在踏蹬过程中,运动员的肌肉用力情况存在一定的差异,全能运动员与公路运动员相比,肌肉用力比较平均,肌力也相对要大 相似文献
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D J Sanderson 《Journal of sports sciences》1991,9(2):191-203
The intent of this study was two-fold. The first aim was to investigate how cyclists orient forces applied by the feet to the pedals in response to varying power output and cadence demands, and the second was to assess whether competitive riders responded differently from recreational riders to such variations. One group consisted of US Cycling Federation category II licensed competitive cyclists (n = 7) and the second group consisted of recreational cyclists with no competitive experience (n = 38). The subjects rode an instrumented stationary 10-speed geared bicycle mounted on a platform designed to provide rolling and inertial resistance for six pedal rate/power output conditions for a minimum of 2 min for each ride. The pedalling rates were 60, 80 and 100 rev min-1 and the power outputs 100 and 235 W. All rides were presented in random order. The forces applied to the pedals, the pedal angle with respect to the crank and the crank angle were recorded for the final 30 s of each ride. From these data, a number of variables were computed including peak normal and tangential forces, crank torque, angular impulse, proportion of resultant force perpendicular to the crank, and pedal angle. Both the competitive and recreational groups responded similarly to increases in cadence and power output. There was a decrease in the peak normal forces, whereas the tangential component remained almost constant as cadence was increased. Regardless of cadence, the riders responded to increased power output demands by increasing the amount of positive angular impulse. All the riders had a reduced index of effectiveness as cadence increased. This was found to be the result of the large effect of the forces during recovery on this calculation. There were no significant differences between the two groups in each of these variables over all conditions. It was concluded that the lack of difference between the groups was a combined consequence of the limited degrees of freedom associated with the bicycle and that the relatively low power output for the competitive riders was insufficient to discriminate or highlight superior riding technique. 相似文献
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Diefenthaeler F Coyle EF Bini RR Carpes FP Vaz MA 《Sports biomechanics / International Society of Biomechanics in Sports》2012,11(1):10-19
The purpose of this study was to analyze pedaling cadence, pedal forces, and muscle activation of triathletes during cycling to exhaustion. Fourteen triathletes were assessed at the power output level relative to their maximal oxygen uptake (355 +/- 23 W). Cadence, pedal forces, and muscle activation were analyzed during start, middle, and end test stages. Normal and tangential forces increased from the start to the end of the test (-288 +/- 33 to -352 +/- 42 N and -79 +/- 45 to -124 +/- 68 N, respectively) accompanied by a decrease in cadence (96 +/- 5 to 86 +/- 6 rpm). Muscle activation increased from the start to the middle and the end in the gluteus maximus (27 +/- 5.5% and 76 +/- 9.3%) and in the vastus lateralis (13 +/- 3.5% and 27 +/- 4.4%), similar increase was observed from the start to the end in the rectus femoris and the vastus medialis (50 +/- 9.3% and 20 +/- 5.7%, respectively). Greater normal force along with enhanced activation of knee and hip extensor muscles is linked with fatigue and declines in cadence of triathletes during cycling to exhaustion. 相似文献
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The aim of this study was to determine the response of cyclists to manipulations of cadence and power output in terms of force application and plantar pressure distribution. Two groups of cyclists, 17 recreational and 12 competitive, rode at three nominal cadences (60, 80, 100 rev x min(-1)) and four power outputs (100, 200, 300, 400 W) while simultaneous force and in-shoe pressure data were collected. Two piezoelectric triaxial force transducers mounted in the right pedal measured components of the pedal force and orientation, and a discrete transducer system with 12 transducers recorded the in-shoe pressures. Force application was characterized by calculating peak resultant and peak effective pedal forces and positive and negative impulses. In-shoe pressures were analysed as peak pressures and as the percent relative load. The force data showed no significant group effect but there was a cadence and power main effect. The impulse data showed a significant three-way interaction. Increased cadence resulted in a decreased positive impulse, while increased power output resulted in an increased impulse. The competitive group produced less positive impulse but the difference became less at higher cadences. Few between-group differences were found in pressure, notable only in the pressure under the first metatarsal region. This showed a consistent pattern of in-shoe pressure distribution, where the primary loading structures were the first metatarsal and hallux. There was no indication that pressure at specific sites influenced the pedal force application. The absence of group differences indicated that pressure distribution was not the result of training, but reflected the intrinsic relationship between the foot, the shoe and the pedal. 相似文献
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The aim of this study was to determine the response of cyclists to manipulations of cadence and power output in terms of force application and plantar pressure distribution. Two groups of cyclists, 17 recreational and 12 competitive, rode at three nominal cadences (60, 80, 100 rev min -1 ) and four power outputs (100, 200, 300, 400 W) while simultaneous force and in-shoe pressure data were collected. Two piezoelectric triaxial force transducers mounted in the right pedal measured components of the pedal force and orientation, and a discrete transducer system with 12 transducers recorded the in-shoe pressures. Force application was characterized by calculating peak resultant and peak effective pedal forces and positive and negative impulses. In-shoe pressures were analysed as peak pressures and as the percent relative load. The force data showed no significant group effect but there was a cadence and power main effect. The impulse data showed a significant three-way interaction. Increased cadence resulted in a decreased positive impulse, while increased power output resulted in an increased impulse. The competitive group produced less positive impulse but the difference became less at higher cadences. Few between-group differences were found in pressure, notable only in the pressure under the first metatarsal region. This showed a consistent pattern of in-shoe pressure distribution, where the primary loading structures were the first metatarsal and hallux. There was no indication that pressure at specific sites influenced the pedal force application. The absence of group differences indicated that pressure distribution was not the result of training, but reflected the intrinsic relationship between the foot, the shoe and the pedal. 相似文献
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The aim of this study was to determine the effect of five pedal crank arm lengths (110, 145, 180, 230 and 265 mm) on hip, knee and ankle angles and on the peak, mean and minimum power production of 11 males (26.6+/-3.8 years, 179+/-8 cm, 79.6+/-9.5 kg) during upright cycle ergometry. Computerized 30 s Wingate power tests were performed on a free weight Monark cycle ergometer against a resistance of 8.5% body weight. Joint angles were determined, with an Ariel Performance Analysis System, from videotape recorded at 100 Hz. Repeated-measures analysis of variance and contrast comparisons revealed that, with increasing crank arm lengths, there was a significant decrement in the minimum hip and knee angles, a significant increment in the ranges of motion of the joints, and a parabolic curve to describe power production. The largest peak and mean powers occurred with a crank arm length of 180 mm. We conclude that 35 mm changes in pedal crank arm length significantly alter both hip and knee joint angles and thus affect cycling performance. 相似文献
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The aim of this study was to determine the effect of five pedal crank arm lengths (110, 145, 180, 230 and 265 mm) on hip, knee and ankle angles and on the peak, mean and minimum power production of 11 males (26.6 +/- 3.8 years, 179 +/- 8 cm, 79.6 +/- 9.5 kg) during upright cycle ergometry. Computerized 30 s Wingate power tests were performed on a free weight Monark cycle ergometer against a resistance of 8.5% body weight. Joint angles were determined, with an Ariel Performance Analysis System, from videotape recorded at 100 Hz. Repeated-measures analysis of variance and contrast comparisons revealed that, with increasing crank arm lengths, there was a significant decrement in the minimum hip and knee angles, a significant increment in the ranges of motion of the joints, and a parabolic curve to describe power production. The largest peak and mean powers occurred with a crank arm length of 180 mm. We conclude that 35 mm changes in pedal crank arm length significantly alter both hip and knee joint angles and thus affect cycling performance. 相似文献
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Cyclists regularly change from a seated to a standing position when the gradient increases during uphill cycling. The aim of this study was to analyse the physiological and biomechanical responses between seated and standing positions during distance-based uphill time trials in elite cyclists. Thirteen elite cyclists completed two testing sessions that included an incremental-specific cycling test on a cycle ergometer to determine VO2max and three distance-based uphill time trials in the field to determine physiological and biomechanical variables. The change from seated to standing position did not influence physiological variables. However, power output was increased by 12.6% in standing position when compared with seated position, whereas speed was similar between the two positions. That involved a significant increase in mechanical cost and tangential force (Ftang) on the pedal (+19% and +22.4%, respectively) and a decrease (?8%) in the pedalling cadence. Additionally, cyclists spent 22.4% of their time in the standing position during the climbing time trials. Our findings showed that cyclists alternated between seated and standing positions in order to maintain a constant speed by adjusting the balance between pedalling cadence and Ftang. 相似文献
18.
Effective force and economy of triathletes and cyclists 总被引：1，自引：0，他引：1
Candotti CT Ribeiro J Soares DP De Oliveira AR Loss JF Guimarães AC 《Sports biomechanics / International Society of Biomechanics in Sports》2007,6(1):31-43
The effective force applied on the crank, the index of pedalling effectiveness, and the economy of movement at 60, 75, 90, and 105 rev/min cadences were examined in nine cyclists and eight triathletes. Tests were performed on two days. Maximal oxygen uptake was measured and the second ventilatory threshold was estimated on day 1 using a stationary bicycle. On day 2, the four different cadences were tested at about 5% below the second ventilatory threshold. A strain gauge instrumented clip-less pedal mounted on the bicycle enabled us to measure the normal and tangential forces exerted on the pedal, while the pedal and crank angles were monitored with the aid of a video system. Based on this information, the effective force and the index of pedalling effectiveness were calculated. Cyclists produced significantly more effective force and a higher index of pedalling effectiveness at 60 and 75 rev/min and were significantly more economic at all cadences than triathletes. The significant and positive correlation between effective force and economy at all cadences suggests that improvement of the effective force would reflect on economy. 相似文献
19.
CLÁUDIA TARRAGÔ CANDOTTI JERRI RIBEIRO DENISE PASCHOAL SOARES ÁLVARO REISCHAK DE OLIVEIRA JEFFERSON FAGUNDES LOSS ANTÔNIO CARLOS S. GUIMARÃES 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(1):31-43
The effective force applied on the crank, the index of pedalling effectiveness, and the economy of movement at 60, 75, 90, and 105 rev/min cadences were examined in nine cyclists and eight triathletes. Tests were performed on two days. Maximal oxygen uptake was measured and the second ventilatory threshold was estimated on day 1 using a stationary bicycle. On day 2, the four different cadences were tested at about 5% below the second ventilatory threshold. A strain gauge instrumented clip-less pedal mounted on the bicycle enabled us to measure the normal and tangential forces exerted on the pedal, while the pedal and crank angles were monitored with the aid of a video system. Based on this information, the effective force and the index of pedalling effectiveness were calculated. Cyclists produced significantly more effective force and a higher index of pedalling effectiveness at 60 and 75 rev/min and were significantly more economic at all cadences than triathletes. The significant and positive correlation between effective force and economy at all cadences suggests that improvement of the effective force would reflect on economy. 相似文献
20.
Mehdi Kordi Chris Fullerton Louis Passfield Len Parker Simpson 《European Journal of Sport Science》2019,19(2):192-198
Body position is known to alter power production and affect cycling performance. The aim of this study was to compare mechanical power output in two riding positions, and to calculate the effects on critical power (CP) and W′ estimates. Seven trained cyclists completed three peak power output efforts and three fixed-duration trial (3-, 5- and 12-min) riding with their hands on the brake lever hoods (BLH), or in a time trial position (TTP). A repeated-measures analysis of variance showed that mean power output during the 5-min trial was significantly different between BLH and TTP positions, resulting in a significantly lower estimate of CP, but not W′, for the TTP trial. In addition, TTP decreased the performance during each trial and increased the percentage difference between BLH and TTP with greater trial duration. There were no differences in pedal cadence or heart rate during the 3-min trial; however, TTP results for the 12-min trial showed a significant fall in pedal cadence and a significant rise in heart rate. The findings suggest that cycling position affects power output and influences consequent CP values. Therefore, cyclists and coaches should consider the cycling position used when calculating CP. 相似文献