Exercise with an elliptical trainer
Exercise with an elliptical trainer (ET) was shown to benefit the cardiorespiratory condition and some institutions include it in fitness for rehabilitation purposes. Despite the benefits of the elliptical training to the cardiovascular fitness, no research has been performed to find the effects of the elliptical exercise on the lower-limbs joints and to improve the elliptical trainer’s design. This research is to obtain a three-dimensional dynamic analysis of the lower limb during elliptical exercise and level walking that will determine the difference of load on different areas of the lower limb.
This is Fifteen male adults were picked to study the difference between the three-dimensional dynamic analysis data as well as the movement of the center of body mass, lower-limb joint angles pedal, moments, pedal reaction force (PRF) and ground reaction force (GRF). The rate and length of the pedal was set to match the data measured while level walking without workload.
The instrument used were commercially available elliptical trainer from Cycling & Health Tech industry R&D Center in Taiwan, six-component force transducer provided by Bertec Corporation which is use to measure the PRF at the right pedal, force plates from Advance Mechanical technology Inc. which measures the GRF, and the Vicon512, the seven-camera motion-analysis system from Oxford Metrics Group in United Kingdom which gets the three-dimensional kinetics data. The measurements were all taken synchronously.
After obtaining the data, the data from both activities were put into the SPSS 10.0 for a paired t-test statistical analysis at 5% level of significance. The mean pedal rates and step lengths were 52.20 rounds per minute with standard deviation of 2.34 and 50.56 cm with standard deviation of 2.14 cm, respectively.
The vertical PRF in the early stage was found to be smaller than the GRF, but the medial and posterior were larger, it was also found PRF to occur on the swing, loading rates at the heelstrike were smaller in elliptical exercise than on level walking, the hip, knee, and ankle peak flexion angles were higher during elliptical exercise, and peak moments at the hip flexor and knee extensor where higher, while peak moments at the ankle plantar flexor and all abductors were lower.
The study showed that the elliptical exercise has a more optimum level of vertical PRF and loading rates than in level walking at the expense of greater hip flexor and knee extensor moments.
The result showed that the lower-limb joints kinematics and dynamics was caused by the locomotor system of the controlled pedal trajectory. The future use of the elliptical trainer in athletic and rehabilitation purposes should include the joint function and muscle strength of the patient and it is also recommended that the design need to be change to improve the mobility of the pedal system and reduce the slope of the pedal ellipse.