11th conference of the International Sports Engineering Association, ISEA 216 Delft University of Technology; July 12 th Joint Torque Evaluation of Lower Limbs in Bicycle Pedaling Hiroki Yamazaki Akihiro Matsuda University of Tsukuba, Japan 1
Previous study Outline This study 5 Joint torque [N m] -5 Subject A Subject B Subject C Subject D Subject E -1 45 9 135 18 225 27 315 36 Via Nirone 7-ALU (Bianchi Corp.) was applied for tests Ankle angle [deg] 18 135 9 45 Linear -3-2 -1 1 2 3 Normal force [N] 5 W 1 W 15 W Wattbike (Wattbike Corp.) was applied for tests Ankle angle[deg] 18 16 14 12 1 8 6 4 2-2 Non-linear -1 Linear 1 Normal force[n] Relationship between normal force in the rotation direction of a bicycle crank and ankle angle 2 2 W 25 W 3 W 1 amateur cyclist as a subject 5 amateur cyclists as subjects 3 Maximum joint torque power[w] 3 25 2 15 1 5 Crank angle[deg] Knee joint torque A B C D E Subjects Maximum joint torque power Ankle joint Knee joint Hip joint Joint torque and joint torque power were evaluated by pedaling system of this study
Purpose / Introduction Evaluating joint torque of lower limbs using our bicycle pedaling system Mechanism of bicycle pedaling The driving force is obtained by human leg power leg power applied to pedals is categorized two forces Effective force Tangential component of leg power Non-effective force Normal component of leg power Not all leg power is converted into driving force To reduce futile forces in bicycle pedaling, Directions of human leg power applied to pedals are crucial Effective force Force (N) Human leg power 3 2 1-1 45 futile force 9 135 18 Bicycle pedal 225 Crank Angle (Degrees) Non- effective force Effective Force Human Leg Power 27 315 36 3
Introduction In previous research, We developed newly biaxial load cells The load cells are designed to imitate cleats The advantage of this load cells is to be able to measure force of biaxial directions Cyclists can be use their own bicycles for performance test Almost same size Rated capacity of horizontal direction ±5N Plastic cleat made in Shimano Corp. Developed biaxial load cells Rated capacity of vertical direction ±1N 4
In previous research, Images of pedaling motion Introduction Image analysis using high-speed camera X 1 : Greater trochanter X 2 : Knee X 3 : Ankle X 4 : Toe γ : Ankle angle Modeling of lower limbs was conducted for the following 2 reasons, To convert the measured force into effective and non-effective force To obtain kinematic data for the lower limb motion 5 X 2 Thigh (,) Lower leg γ X 3 X 4 X 1 Foot Link mechanism of lower limb motion
In previous research, Images of pedaling motion Introduction Image analysis using high-speed camera The modeling of lower limb motion have weak point Each time the pedaling output and cadence changes, the ankle angle was obtained directly from image analysis using high-speed cameras X 2 Thigh (,) Lower leg γ X 3 X 4 X 1 Foot Link mechanism of lower limb motion X 1 : Greater trochanter X 2 : Knee X 3 : Ankle X 4 : Toe γ : Ankle angle 5
In previous research, Images of pedaling motion Introduction Image analysis using high-speed camera Link mechanism of lower limb motion In this study, an approximation method of relationship between the ankle angle and normal force in the rotation direction of a bicycle crank was proposed. X 2 Thigh (,) Lower leg γ X 3 X 4 X 1 Foot X 1 : Greater trochanter X 2 : Knee X 3 : Ankle X 4 : Toe γ : Ankle angle 5
Modeling of lower-limb motion Test condition Subjects Applied bicycle :5 amateur male cyclists :Wattbike (Wattbike Corp.) Pedaling output : 2, 25, 3 W Cadence : 8, 9, 1 rpm Recording frequency : 5 Hz Horizontal and vertical loads of legs were recorded for 3 seconds Subject data Subject Age Height [m] Mass [kg] BMI [kg/m 2 ] A 22 1.75 62.65 2.45 B 23 1.75 73.65 24.25 C 24 1.72 65.4 22.1 D 23 1.65 64.1 23.68 E 24 1.7 67.2 23.25 Standard Deviation.894.389 3.83 1.3 6
Modeling of lower-limb motion Ankle angle [deg] 18 16 14 12 1 8 6 4 2-2 upstroke -1 Ankle angle[deg] 18 16 14 12 1 downstroke 9 8 downstroke 6 6 downstroke 1 Normal force [N] Pedaling output Pedaling output Pedaling output 2 2 W 25 W 3 W 3 4 2-2 upstroke -1 1 Normal force[n] 2 2 W 25 W 3 W 3 Ankle angle [deg] 18 15 12 3-2 upstroke -1 1 Normal force [N] 8rpm 9rpm 1rpm These figure showed that this relationship was not significantly affected by pedaling output and cadence in downstrokes. 1 f n 2 : linear equation was applied to approximation for the downstroke 2 2 W 25 W 3 W 3 1 f n 2, : Constant parameters for each subject : Ankle angle : Normal force in the rotation direction of a bicycle crank 7
Modeling of lower-limb motion Ankle angle [deg] 18 16 14 12 1 8 6 4 2-2 -1 1 1 f n 2 Normal force [N] Pedaling output Pedaling output Pedaling output 2 2 W 25 W 3 W 3 Ankle angle[deg] 18 16 14 12 1 8 6 4 2-2 -1 1 Normal force[n] 2 2 W 25 W 3 W : linear equation was applied to approximation for the downstroke 3 Ankle angle [deg] 18 15 12 9 6 3-2 -1 1 Normal force [N] 8rpm 9rpm 1rpm These figure showed that this relationship was not significantly affected by pedaling output and cadence in downstrokes. 2 2 W 25 W 3 W 3 1 f n 2, : Constant parameters for each subject : Ankle angle : Normal force in the rotation direction of a bicycle crank 7
Modeling of lower-limb motion Ankle angle [deg] 18 16 14 12 1 8 6 4 2-2 -1 1 Normal force [N] 2 2 W 25 W 3 W 3 Ankle angle[deg] 18 16 14 12 1 8 6 4 2-2 -1 1 Normal force[n] 2 2 W 25 W 3 W 3 Ankle angle [deg] 18 15 12 9 6 3-2 -1 1 Normal force [N] 8rpm 9rpm 1rpm These figure showed that this relationship was not significantly affected by pedaling output and cadence in downstrokes. f 1 n 2 Pedaling output Pedaling output Pedaling output Two variables used in the approximation method were determined by using relationship Subject γ 1 γ 2 2 2 W 25 W 3 W Approximate expression parameters A.486 12.7 B.695 17.712 C.264 19.87 D.615 97.832 E.516 1.47 3
Construction of evaluation system Calculation method for joint torque Joint torque is the resistive force acting on the body due to the influence of external forces Cyclists are able to recognize their lower limbs behavior objectively Joint torque was calculated by using free body diagram The free body diagram separates the lower limb into three segments(thigh, lower leg and foot). Thigh Positive joint torque Negative joint torque : Extension torque : Flexion torque Lower leg Equation of motion for each segment m I k k x k k f k, P f k, P D m k, cgp f k, P Pk, cgd f k, D Tk, P k g T k, D Foot Free body diagram 8
Construction of evaluation system Calculation method for joint torque power Joint torque power(p t ) is a calculated value based on joint torque(jt) and joint angular velocity(jav) Cyclists are able to estimate the action of virtual muscles Joint torque(jt) was calculated by the free body diagram Joint angular velocity(jav) was calculated by differentiating the joint angle based on the link mechanism P t JT JAV Definition of joint torque power Joint torque Joint angular velocity Joint torque power Extension torque (+) Extension (+) Positive power (+) Flexion (-) Negative power (-) Flexion torque (-) Extension (+) Negative power (-) Flexion (-) Positive power (+) 9
Performance test Test condition Subjects Applied bicycle :5 amateur male cyclists :Wattbike (Wattbike Corp.) In tests, subjects were ordered following condition Pedaling output : 2 W Cadence : 9 rpm Pedaling in 3 sec Experimental condition 1
Test result (knee joint torque) Knee joint torque in each subject The difference is remarkable from 9 to 18 Flexion torque was exerted at about 1 of crank angle by subject D at about 13 of crank angle by subject B, C and E at about 16 of crank angle by subject A 5 Joint torque [N m] -5 Subject A Subject B Subject C Subject D Subject E -1 45 9 135 18 225 27 315 36 Crank angle[deg] Knee joint torque 11
Test result (knee joint torque) Knee joint torque in each subject The difference is remarkable from 9 to 18 Flexion torque was exerted at about 1 of crank angle by subject D at about 13 of crank angle by subject B, C and E at about 16 of crank angle by subject A Joint torque [N m] 5-5 Subject A Subject B Subject C Subject D Subject E Joint torque [N m] 5 Subject A Subject B Subject C Subject D Subject E -1 45 9 135 18 225 27 315 36-5 9 135 18 Crank angle[deg] Knee joint torque Crank angle[deg] 11
Test result (knee joint torque) Knee joint torque in each subject In previous research, trained cyclist exerted flexion knee joint torque at about 135 of crank angle Subject B, C and E were pedaling well in dwonstorkes Joint torque [N m] 5 Subject A Subject B Subject C Subject D Subject E Flexion Flexion Flexion -5 9 135 18 Crank angle[deg] Subject D B, C, E A
Test result(joint torque power) Maximum joint torque power in each subject Evaluation of maximum joint torque power allows us to estimate the action of muscles of lower limbs in bicycle pedaling Maximum joint torque power[w] 3 25 2 15 1 5 Ankle joint Knee joint Hip joint A B C D E Subjects Maximum each joint torque power Positive joint torque power means concentric working of muscle 5 subjects were classified into 3 groups A, B and C were classified into maximum knee joint torque power group D was classified into maximum ankle joint torque power group E was classified into maximum hip joint torque power group 12
Test result of subject A, B and C Maximum joint torque power in each subject Maximum joint torque power[w] 3 25 2 15 1 5 Ankle joint Knee joint Hip joint A B C D E Subjects Maximum knee joint torque power Joint torque power [W] 3 25 2 15 1 5-5 -1-15 -2 45 9 135 18 225 Crank angle[deg] Subject A Subject B Subject C 27 315 36 Extension Subject A, C Flexion Subject B Subject A, B and C were worked to advantage the positive joint torque power in the knee joint The maximum knee joint torque power was generated at about 9 or 18 of crank angle A and C were worked maximum extension torque power at about 9 of crank angle B was worked maximum flexion torque power at about 18 of crank angle 13
Test result of subject D Maximum joint torque power in each subject Maximum joint torque power[w] 3 25 2 15 1 5 Ankle joint Knee joint Hip joint A B C D E Subjects Maximum ankle joint torque power Joint torque power [W] 2 15 1 5-5 Extension Subject D was worked to advantage the positive ankle joint torque power The maximum ankle joint torque power was generated at about 13 of crank angle Maximum extension torque power of ankle joint was exerted because subject D tends to move the ankle joint mainly -1 45 9 135 18 225 27 315 36 Crank angle[deg] 14
Test result of subject E Maximum joint torque power in each subject Joint torque power [W] Maximum joint torque power[w] 2 15 1 3 5-5 -1 25 2 15 1 5 Ankle joint Knee joint Hip joint A B C D E Subjects Maximum hip joint torque power 45 9 135 18 225 Crank angle[deg] 27 315 36 Extension Subject E was worked to advantage the positive hip joint torque power The maximum hip joint torque power was generated at about 13 of crank angle Maximum extension torque power of hip joint was exerted because subject E was generated maximum hip joint torque and hip joint angular velocity at the same time 15
Conclusion Performance tests with 5 armature cyclists were conducted using developed bicycle pedaling system with small biaxial load cells Dynamic behavior of ankles in pedaling were analyzed by high speed camera system. From the results, a linear relationship between ankle angle and normal force of crank was proposed f 1 n 2 This relationship was applied to approximation of relationships between ankle angle and nominal force in downstorkes, especially. Joint torque power of each subjects in performance test were calculated and we investigate how each subject use their muscles of lower limbs in bicycle pedaling. Three subjects (A,B,C) showed same tendency of pedaling This might means that they are pushing down or pulling up the bicycle pedal using a peripheral muscle group of knee joint Two subjects are different from the other subjects, this might means that they are pushing down using a peripheral muscle of ankle or hip joint
Thank you for your attention 17