Analyzing the influences of bicycle suspension systems on pedaling forces and human body vibration

Front and rear suspensions are commonly equipped on bicycles for the purpose of riding comfort especially for mountain bicycle. Suspension system includes damper for shock absorbing and spring for rebounding. Therefore suspension system would increase leg muscle forces for riding bicycle since damper dissipates some energy. ADAMS‎®‎/LifeMOD‎®‎ are proposed in this research to establish a bicycle-human integrated multibody dynamic model to investigate the impact of bicycle suspensions on cyclist’s leg muscle forces under various pedaling conditions and human body vibration for evaluation of riding comfort. Muscles studied include adductor magnus, rectus femoris, vastus lateralis and semitendinosus. Comfort analyses include the vibrating acceleration in vertical direction of lower torso and scapula. Pedaling conditions include riding on flat road, over a road bump, and climbing slope. The results indicate that suspension system increases the pedaling forces of vastus lateralis and semitendinosus. However suspension system decreases the pedaling forces of adductor magnus and rectus femoris. Suspension systems, especially the rear suspension, may effectively reduce human body vibrating acceleration. The integrated model built in this research may be used as reference for designing bicycle suspension systems. Also, the results of this study may be used as a basis of leg weight training to strengthen certain muscles for long-distance off-road cyclists

Simulation of Riding a Full Suspension Bicycle for Analyzing Comfort and Pedaling Force

AbstractRecently, there is an increasing interest on bicycle riding for recreation or fitness purpose. Bicycles are also accepted as urban transportation due to the consciousness of environmental protection. For a more comfortable riding experience, many bicycles are equipped with a suspension system including a front suspension fork and/or rear suspension. However, when a suspension system is added to a bicycle, it makes riding a little heavier since suspension dissipates some pedalling energy. This paper discusses front and rear suspensions corresponding to rider comfort and pedalling effort when riding on a rough road and smooth road. A human body computer model LifeMOD® is employed to model the cyclist. Dynamic analysis software ADAMS® is employed to analyze human body vibration and leg muscle forces of bicycle riding. Human body acceleration vs. vibration frequencies are used as the comfort criteria. The results show that a suspension system may effectively reduce high frequency vibration of the human body when riding on a rough road. Pedalling forces are mostly contributed by the biceps femoris and semitendinosus. The suspension system would increase the pedaling forces of femoris and semitendinosus. Other leg muscles have a minor effect on pedaling forces. Results obtained from this research are useful for the design of bicycle suspension systems with better comfort and less loss of pedalling efficiency

Muscles force and joints load simulation of bicycle riding using multibody models

AbstractA three dimensional multibody dynamic numerical model using LifeMOD and ADAMS is presented to simulate and analyze the load of wrists, shoulders, leg muscles, knees, and ankles of bicycle riding. Applications of ADAMS/LifeMOD are widely used, for example, rifle shot stress to the human body, golf swing, Tae Kwon Do side kick simulation, rowers paddle boat. Applications are even in the medical research including dynamic stability of human spine simulation, and thoracic and lumbar dynamic simulation. Vertical (height) and horizontal position of bicycle saddle are adjusted in the three dimensional multibody model to simulate muscles force for city bicycle riding and race bicycle riding. Besides, loads of shoulders, wrists, knees, and ankles are analyzed between postures of city bicycle riding and race bicycle riding. The objective of this research is to obtain a suitable posture either for city bicycle riding or race bicycle riding to prevent sports injuries. ADAMS/LifeMOD simulation of riding city bicycle and race bicycle with different riding postures is presented in this paper. Several main findings include: (1) If the bicycle saddle is too high, soleus force would be increased. (2) If the bicycle saddle is too low, biceps femoris and iliacus forces would be increased. (3) The influence on muscles force caused by a little adjustment of distance between saddle and handlebars may be ignored. (4) Posture of riding race bicycle bends upper body more and increases iliacus forces but decreases soleus force. (5) Because race bicycle riding posture bends upper body, the joints loads on lumbar, shoulders and elbows are greatly increased