To investigate the effects of pedal degree on the biomechanical characteristics of the healthy adults' lower limbs during stepping on the pinnacle trainer.The purpose of this study are compare the biomechanical characteristics of low limbs at different angle of pedal during stepping on Pinnacle trainer. The investigators hope to provide this outcome to therapists can make the rehabilitation training more effective and delay the disease progression of KOA patients.

The pedal angle influences the force distribution in the lower extremities. Although we have seen the angle of the pedal selected of the bicycle and a lot of insole paper, the previous paper did not see adjusting the pedal angle of the pinnacle trainer. However, the joint loading and force distribution during stepping on a pinnacle trainer with various pedal angle are unknown. The investigation of biomechanics of the lower extremity is important to provide information about the joint loadings and prevent potential injuries during exercise.According to the World Health Organization, by 2050, people over 60 years old will account for nearly 22% of the world's population. Of that 22%, a conservative estimate of 15% will have symptomatic OA. It is estimated that by 2050, nearly 130 million people worldwide will suffer from OA, and 40 million people will gradually affect their lives and be severely disabled due to osteoarthritis by 2050. Knee Osteoarthritis accounts for more than 80% of the global OA disease burden. And previous studies suggested that the use of the Pinnacle Trainer for individual with knee OA is effective on the improvement of pain intensity, physical functions and the muscular strength of the low extremity. And the internal knee abduction moment demonstrated a tendency toward to reduce after the Pinnacle Trainer intervention. Hence, the reduction of excessive internal knee abduction moment is beneficial for some users. On the other hand, the internal knee abduction moment is related to the severity of the knee OA.

The majority of research has focused specifically on the effect of lateral wedge insoles at the knee, and numerous of studies have concentrated on pedals on stationary cycling. Those studies suggested that the foot everted position reduced the KAM. However, few studies investigated the angle of pedal during the CKC exercise equipment. However, the biomechanical characteristics during stepping on Pinnacle Trainer with different pedal angles are unknown. The investigators wanted to explore the biomechanical characteristics of lower extremity during pinnacle trainer with different pedal angles and further explore whether KAM can be effectively reduced by changing the angle of the wedge to assist the training of KOA patients.

The purpose of this study are compare the biomechanical characteristics of low limbs at different angle of pedal during stepping on Pinnacle trainer. The investigators hope to provide this outcome to therapists can make the rehabilitation training more effective and delay the disease progression of KOA patients.

Inclusion Criteria:

30 healthy individuals above 20 years and will be recruited in this study. 30 participants will be recruited with considering the inclusion criteria as follows:

1. 20 years old above
2. Able to perform regular exercise
3. Able to understand Chinese or Taiwanese language
4. Healthy adult (no skeletal muscle, neurological disease, normal BMI (18.5≦BMI<25.0), and no disease that will affect training.

Exclusion Criteria:

1. Having illness or diseases that cannot perform physical exercise
2. Having any kinds of chronic disease that might be more activated by performing Pinnacle training such as cardiovascular diseases, chronic respiratory diseases, osteoporosis, etc.
3. Having chronic diseases that cannot perform Pinnacle training according to the experimental protocols such as blindness, deafness and hearing impairment, etc.

The subject already knows the angle of the pedal when he steps on the pedal, because there are only three angles.