輪椅後輪傾斜角是一很重要影響輪椅運動的參數，一般建議依能量耗損最小為原則選擇後輪傾斜角角度。本研究的目的為探討推動輪椅時針對後輪傾斜角（0度，9度，15度）及不同速度（1公尺/秒及2公尺/秒）時對上肢能量需求與能量喪失之效應。12位健康受試者（平均年齡22.3±1.6歲）參與此研究，使用動作分析系統收取三維上肢運動學資料與一組具有三軸力感測器之輪子拮取動力學資料。上肢分為三個（上臂、前臂和手）連桿系統。機械功與功率傳遞功被視為能量需求，此外，機械功與功率傳遞功的差值被定義為上肢或個別肢段在推動不同輪椅後輪傾斜角與不同速度時能量喪失的指標。
比較上肢功差值(機械功與功率傳遞功之功差值）於15度後輪傾斜角度時統計上大於0度和9度的結果。上臂與前臂功差值較大在此三個後輪傾斜角度中。前臂功差值在統計上15度後輪傾斜角大於0度和9度，但0度和9度之間沒有統計上的差異。這個結果顯示推動後輪傾斜角15度時有較大的能量喪失。
快速推動輪椅比慢速推動輪椅在此三個後輪傾斜角中有較大機械功與功率傳遞功的需求。比較快速推動輪椅與慢速推動輪椅功差值，在快速時上臂功差值大約兩倍多於慢速，前臂大約一至兩倍，手大約兩倍。
為有效率推動輪椅而選擇後輪傾斜角時，必須考慮到使用者個人上肢肌肉表現。特別在快速推動輪椅時，後輪傾斜角15度時比0度或9度皆需較大的能量耗損與較大肌肉活動。上臂比其他肢段需要較大的能量。當快速推動輪椅時，較大的功與較大的功差值意味著增加能量的需求與能量的喪失，可能與上肢需要較大的穩定度有關。

The wheel camber is an important parameter that affects wheelchair exercise. It has been suggested that minimization of energy cost is a primary determinant for selection of rear-wheel camber. The purposes of this study were to examine the effects of wheel camber (0º, 9º and 15º) and speed (1 m/s and 2m/s) on energy cost and energy lost for upper extremity during wheelchair propulsion. Twelve healthy subjects (mean age 22.3±1.6 years) participated in this study. A motion-tracking system and an instrumented wheel were used to collect the 3D kinematic and kinetic data for the upper extremity. The upper extremity was treated as a three-segment (upper arm, forearm, and hand) linked system. We calculated mechanical work and power flow work for determining energy cost. In addition, we used the discrepancy between these two work estimates as an index to determine wheel camber and speed effects on the energy lost in the upper extremity and individual segments.
The work discrepancies in these three cambers were greater on the upper arm and forearm. The work discrepancy in forearm and total upper extremity was significantly greater in 15° of camber than 0° and 9° but no significant difference was found between 0° and 9°. The result indicated greater energy lost to propel the wheelchair with 15° of camber.
The demands of the mechanical work and the work related to power flow for wheelchair propulsion at the three camber angles were greater at the fast speed than at the low speed. As compared to the work discrepancy at the slow speed, that at the fast speed was approximately more than twice for the upper arm, once to twice for the forearm, and twice for the hand.
The individual’s muscle performance in upper extremity should be taken into consideration when choosing camber angle for efficient wheelchair propulsion. 15° of camber requires greater energy consumption and muscle activity than the cambers of 0° or 9° did, particularly for propulsion at a fast speed. The upper arm requires greater energy cost than other segments. For propulsion at the fast speed, the greater work and work discrepancy might be related to increased energy cost and energy loss owing to greater stability demand on the upper extremity.

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