Force-velocity test on a stationary cycle ergometer: methodological recommendations (original) (raw)
Related papers
1995
Changes in muscle activity occur with changes in cycling cadence and power output. An understanding of these changes can aid in strength training and performance evaluation. Although the integrated EMG has been frequently studied, phasic muscle activity is evaluated less often. Phasic activity was measured relative to the crank position from 0o at top dead center (TDC) through a fill revolution. Four muscles on three experienced recreational cyclists were monitored at cadences of 60rpm, 80rpq and l00rpm and at power levels of 150W, 300W, and 450W. Surface electrodes and videography were utilized to determine the start and stop position of muscle activity relative to each crank revolution. A fill-rectification of the raw EMG signal was then used to determine activity above the threshold. Rectus femoris activity started earlier in the crank cycle with each increase in cadence. However, it stopped later for only the first increment in cadence and remained constant for the second. These...
1995
Seven subjects pedalled on a Monark cycle ergometer as fast as possible for approximately 7 s against four different resistances which corresponded to braking torques (T B) equal to 19, 38, 57 and 76 N · m at the crank level. Exercise periods were separated by 5-min recovery periods. Pedal velocity was recorded every 50 ms by means of a disc with 360 slots fixed on the flywheel, passing in front of a photo-electric cell linked to a microcomputer which processed the data. Every 50 ms, the time necessary to perform half a pedal revolution (t 1/2) was computed by adding the 50-ms periods necessary to reach 669 slots (the number of slots corresponding to half a pedal revolution). To measuret 1/2 to an accuracy better than 50 ms, this time was computed by a linear interpolation of the time-slot number relationship. Power (P) was averaged duringt 12 by adding the power dissipated against braking torque and the power necessary to accelerate the flywheel. The torque-velocity (T-ν) relationship was studied during the acceleration phase of a sprint against a single TB by computing every 50 ms the relationship between ν and T (N · m), equal to the sum ofT B and the torque necessary to accelerate the flywheel at the same time. The T-ν relationships calculated from the acceleration phase of a single all-out exercise were linear and similar to the previously described relationships between peak velocity and braking force. These relationships can be expressed as follows: ν = ν0,acc (1 −T/T 0,acc) where ν is pedal velocity,T the torque exerted on the crank andT 0,acc and ν0,acc have the dimensions of maximal torque and maximal velocity respectively. Based on this model, maximal power (P max,acc) is calculated as 0.257ν0, accT 0, acc. Maximal powerP max,acc measured with the acceleration method was independent of braking torqueT B and slightly higher thanP max calculated from the relationship between peak velocity andT B.
The aim of this work was to verify the hypothesis that the lowering of the pedalling rate (elicited by the increase of the exterior load) during maximal efforts performed with identical work amount causes the growth of the generated power (until the maximal values are reached) and next its fall and does not influence the gross and net mechanical efficiency changes. The above experiment was conducted with 13 untrained students who performed 5 maximal efforts with the same work amount. The first was the 30 s maximal effort (Wingate test) with the load equal 7.5% of the body weight (BW). The amount of work performed in this test was accepted as the model value for following tests to achieve. Every 3 days, each examined had next trials consisting of maximal efforts on the cycle ergometer with loads of: 2.5, 5, 10, 12.5% BW and lasting until the value of power reached in the 30 s Wingate test occurred. Changing of the external load elicited various pedalling velocity. The force-velocity (F-v) and power-velocity (P-v) dependence was calculated for every examined subject basing on the results of performed maximal efforts. The maximal power (P max ) and optimal velocity (v o ) were calculated basing on the P-v relationship depicted with the second order polynomial equation. The gas analyser (SensorMedics) equipped with the 2900/2900c Metabolic Measurements Cart/System software was used as for the oxygen output measuring during maximal efforts performance and in the resting phase. The ventilation and gas variable changes were monitored breath-by-breath in the open ventilation system. The POLAR-SportTester was used for the heart retraction (HR) measurement during both: efforts and resting. The capillary blood was taken from the fingertip before the test and: immediately after it, every 2 min for the first 10 min of the rest and in the 20 th min of resting. The blood was used for the acid-base balance determination with the use of the blood gas analyser -Ciba-Corning 248. The average pedalling rate decreased during effort from 151.5 rpm to 80 rpm and the power grew from 293.5 W to 761 W along with the increase of the load from 2.5% to 12.5% BW. Powers varied among specific trials with the Biol.Sport 22(1), 2005 36
Biomechanical measures of short-term maximal cycling on an ergometer: a test-retest study
Sports Biomechanics, 2020
Biomechanical measures of short-term maximal cycling on an ergometer: a test-retest study An understanding of test-retest reliability is important for biomechanists, such as when assessing the longitudinal effect of training or equipment interventions. Our aim was to quantify the test-retest reliability of biomechanical variables measured during short-term maximal cycling. Fourteen track sprint cyclists performed 3 x 4 s seated sprints at 135 rpm on an isokinetic ergometer, repeating the session 7.6 ± 2.5 days later. Joint moments were calculated via inverse dynamics, using pedal forces and limb kinematics. EMG activity was measured for 9 lower limb muscles. Reliability was explored by quantifying systematic and random differences within-and between-session. Within-session reliability was better than between-sessions reliability. The test-retest reliability level was typically moderate to excellent for the biomechanical variables that describe maximal cycling. However, some variables, such as peak knee flexion moment and maximum hip joint power, demonstrated lower reliability, indicating that care needs to be taken when using these variables to evaluate biomechanical changes. Although measurement error (instrumentation error, anatomical marker misplacement, soft tissue artefacts) can explain some of our reliability observations, we speculate that biological variability may also be a contributor to the lower repeatability observed in several variables including ineffective crank force, ankle kinematics and hamstring muscles' activation patterns.
The effect of pedal crank arm length on joint angle and power production in upright cycle ergometry
Journal of Sports Sciences, 2010
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 II 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.
Medical engineering & physics, 2014
Rehabilitation of persons with pareses commonly uses recumbent pedalling and a rigid pedal boot that fixes the ankle joint from moving. This study was performed to provide general muscle moments (GMM) and joint power data from able-bodied subjects performing recumbent cycling at two workloads. Twenty-six able-bodied subjects pedalled a stationary recumbent tricycle at 60 rpm during passive cycling and at two workloads (low 15 W and high 40 W per leg) while leg kinematics and pedal forces were recorded. GMM and power were calculated using inverse dynamic equations. During the high workload, the hip and knee muscles produced extensor/flexor moments throughout the extensions/flexions phases of the joints. For low workload, a prolonged (crank angle 0-258°) hip extension moment and a shortened range (350-150°) of knee extension moment were observed compared to the corresponding extension phases of each joint. The knee and hip joints generated approximately equal power. At the high worklo...
Power output and work in different muscle groups during ergometer cycling
European Journal of Applied Physiology and Occupational Physiology, 1986
The aim of this study was to calculate the magnitude of the instantaneous muscular power output at the hip, knee and ankle joints during ergometer cycling. Six healthy subjects pedalled a weight-braked bicycle ergometer at 120 watts (W) and 60 revolutions per minute (rpm). The subjects were filmed with a cine camera, and pedal reaction forces were recorded from a force transducer mounted in the pedal. The muscular work at the hip, knee and ankle joint was calculated using a model based upon dynamic mechanics described elsewhere. The mean peak concentric power output was, for the hip extensors, 74.4 W, hip flexors, 18.0 W, knee extensors, 110.1 W, knee flexors, 30.0 W and ankle plantar flexors, 59.4 W. At the ankle joint, energy absorption through eccentric plantar flexor action was observed, with a mean peak power of 11.4 W and negative work of 3.4 J for each limb and complete pedal revolution. The energy production relationships between the different major muscle groups were computed and the contributions to the total positive work were: hip extensors, 27%; hip flexors, 4%; knee extensors, 39%; knee flexors, 10%; and ankle plantar flexors 20%.
International journal of rehabilitation research. Internationale Zeitschrift für Rehabilitationsforschung. Revue internationale de recherches de réadaptation, 2015
The combined arm-leg (Cruiser) ergometer is assumed to be a relevant testing and training instrument in the rehabilitation of patients with a lower limb amputation. The efficiency and submaximal strain have not been established and thus cannot be compared with alternative common modes of exercise. A total of 22 healthy able-bodied men (n=10) and women (n=12) were enrolled in four discontinuous submaximal graded exercise tests. Each test consisted of seven bouts of 3 min exercise ranging from 20 to 45 W and was performed on, respectively, the Cruiser ergometer, a bicycle ergometer, a handbike, and again the Cruiser ergometer. Cardiorespiratory parameters were measured and rate of perceived exertion was determined. Gross mechanical efficiency (GE) was determined from power output and submaximal steady-state energy cost. Repeated-measures analysis of variance (P<0.05) was used to evaluate the effects of exercise mode, exercise intensity, and sex. No differences in GE and cardiorespi...
The relationship between maximal power and maximal torque-velocity using an electronic ergometer
1996
Eight subjects performed a single allout sprint on a cycle ergometer with strain gauges bonded to the cranks. The crank angle-torque curves of the left and right legs were recorded during ten revolutions using the software package supplied with the ergometer. Torque data were stored every 2° (180 angle-torque data per pedal revolution for each leg). The ergometer was used in the linear mode with the lowest available linear factor (F 1 = 0.01). In this mode, the braking torque (T B) was proportional to cycling velocity ν(T B =F 1ν) and mechanical power was equal toF 1ν2. The relationship between the torque averaged over one revolution and the average velocity of one pedal revolution was studied during the acceleration phase of short allout exercise on an electronic ergometer (eight subjects) and a friction-loaded ergometer (four subjects). The present study showed that it is possible to determine the maximal torque-velocity relationship and to calculate maximal anaerobic power during a single allout sprint using an electronic cycle ergometer provided that strain gauges are bonded to the cranks. The torque-velocity relationships calculated were linear as for a friction loaded ergometer. As expected, the values of torque and maximal power measured with the strain gauges were higher than the corresponding values computed from the data collected during an allout test on a friction loaded ergometer. The torque-angle data collected during a single allout cycling exercise would suggest that angular accelerations of the leg segments and gravitational forces play the main role at high velocity.