HEEL HEIGHT ON GROUND REACTION FORCE DURING A SIT TO STAND

Heel Height On Ground Reaction Force During A Sit To Stand

Table of Contents

Outline3

1. Introduction5

2. Subjects and methods7

2.1. Subjects7

2.2. Methods8

2.3. Procedures8

2.4. Ground reaction force parameters, physical activity and falling risk scores10

2.5. Statistical analysis11

3. Results12

4. Discussion17

References24

Effects of Heel Height on Ground Reaction Force during a Sit to Stand

Outline

This study aimed to examine the relationships between ground reaction force during a sit-to-stand (STS) movement and physical activity and falling risk of the elderly and the difference of the movement characteristics between the young and the elderly. Sixty elderly females who can achieve a STS movement by themselves and 30 healthy young females were measured for ground reaction force during STS movement from a chair, adjusted for lower leg length height. The elderly's physical activity and falling risk were also assessed. Physical activity and falling risk significantly correlated with parameters on force exertion during hip lift-off and knee-hip joint extension phases (|r| = 0.26-0.41). Significant differences were found in ground reaction force parameters of all phases between the young and the elderly and STS movement of the elderly was suggested to result in poor force exertion and slowing down. The above tendency was noticeable in the hip lift-off and knee-hip joint extension phases. In conclusion, force exertion in hip lift-off and knee-hip joint extension phases of STS movement is related to physical activity and falling risk in the elderly. These phases may be useful to evaluate the elderly's physical activity and falling risk.

Sit-to-stand (STS) movement is an important functional task that may become difficult for certain patient populations. The accurate depiction of the requirements for the execution of this task provides useful biomechanical information on the motor ability of a selected patient. In particular, rising from a chair requires adequate torque to be developed by body joints.

Even though the STS movement has been a topic of numerous investigations related to different patient populations, the STS movement strategy of obese subjects has not been analysed yet. In these patients weight conditions and muscular weakness change motion task strategy and, consequently, the torque distributions of hip, knee and ankle joints. Patients with severe obesity present very frequently with postural changes which can cause chronic low back pain. So far, the association of obesity and chronic lower back pain is not clear,9 and it is likely to be more evident in the upper quintile of obesity.10 Low back pain can limit the daily activity of obese patients. STS is likely to be a very good model to assess the ability of obese patients to properly execute daily living tasks.

The main aim of this study was to compare the analysis of STS movement of normal and obese subjects in order to evidence the motion strategies typical of these patients. In order to evidence the fatigue in execution of the task, the STS strategy was analysed for 10 trials. The kinematic and kinetic analyses of STS in obese might also be useful in designing rehabilitative protocols and to assess their ...