Effects of six-week plyometric training incorporated with augmented feedback on ground reaction forces
|Keywords:||增強式運動訓練;下肢力學;地面反作用力;落地技巧指導;plyometric training;landing mechanics;ground reaction forces;augmented feedback||Issue Date:||2011||Abstract:||
近年來,增強式運動訓練常用於運動員的爆發力訓練,對於增進運動員的肌 力、跳高能力以及肌腱勁度皆有非常良好的效果。然而當跳高能力增強時,不可 避免的落地時的地面反作用力也會隨之增加,反而存在組織受傷的風險,然而截 至今天並無增強式訓練與落地時地面反作用力關係的研究。過去曾有研究發現在 神經肌肉訓練時,施以口頭指導或回饋訊息等方式,可降低受試者的地面反作用 力,但未曾有研究探討這樣的指導對於增強式運動訓練是否也會有類似的效應。 因此本研究旨在探討增強式運動訓練結合落地技巧的指導,是否能有效地改變落 地時的地面反作用力。其具體目標有二:(一)檢測增強式運動訓練是否會影響地 面反作用力、落地表現、等速肌力、垂直跳高度以及爆發力、(二)檢測外加落地 技巧指導是否會影響地面反作用力、落地表現、等速肌力、垂直跳高度以及爆發 力。
本研究設計為前瞻性、雙盲性以及隨機分配對照實驗,總計徵召 21 名大專乙 組男性籃球運動員。所有受試者在簽⭺91;研究同意書後,接受身高與體重之量測, 並記錄其年齡、正規訓練強度以及訓練年限等基本資料。受試者在增強式運動訓 練介入前、三週介入後、六週介入後等三個時間點接受主要的測試,測試項目包 括下蹲跳時下肢力學分析、等速肌力、垂直跳高度以及無氧爆發力。在本實驗中, 使用測力板、動作分析系統、等速肌力儀以及垂直跳測試計來分別測量上述之參 數。受試者在下肢力學分析以及垂直跳高度的測試中,測試動作為垂直下蹲跳, 且皆收取四次成功的資料才進行分析。等速肌力儀則是量測受試者動態肌力的工 具,而其數據用以計算力矩最大值以及肌肉力矩值穩定度。另一與運動表現有關 的參數為瑪珈利亞動力測試,受試者執行登階梯的任務。所有的常態分佈的連續 數資料以重複測量變異數分析計算三週或六週運動介入的效益,而非連續數或非常態分佈資料則將以弗來德曼檢定分析。所有的統計皆在 SAS 9.2 版中進行,顯 著水準訂在 α= 0.05,而檢定力則訂在 0.8。
本研究主要結果為:(一)在相同衝量下,六週增強式運動訓練結合落地技巧 指導可以改善運動員落地時下肢力學,對於地面反作用力、吸震率、落地時間以 及膝屈曲角度皆有顯著地改善;(二)六週訓練對於下肢離心肌力有顯著的改善, 但對於其它向心肌力以及力矩值穩定度則沒有明顯效果;(三)六週訓練對於運動 員的運動表現如跳躍能力以及爆發力皆會產生顯著地增加。
此結果顯示增強式運動訓練結合落地技巧指導可以改善運動員落地時的下肢 力學,且同時增加運動員的肌力以及運動表現。然而對於此訓練是否有持續的效 果以及對於場上受傷率是否有影響,則仍需要進一步地研究。此研究為第一篇探 討增強式運動訓練對於地面反作用力的影響,且訓練後可能會加大地面反作用力, 如能外加落地技巧指導,則可降低地面反作用力的衝擊,在越來越多隊伍使用增 強式訓練當作爆發力訓練時,落地技巧指導可預防增強式運動訓練後帶來的副作 用。未來研究人員或教練在利用增強式運動訓練於運動員時,應加入詳細的落地 技巧訓練。
Plyometric training is normally adopted in athletes’ power training that can improve muscle strength, jump height, and tendon stiffness. However, as muscle performances after plyometric training such as jump height improved, it is inevitable that ground reaction forces during landing will also increase and further cause non-contact sports-related injuries. However, no current study has examined the effects of plyometric training on ground reaction force. Past researches had used neuromuscular training, verbal instructions, or feedback to alter the landing mechanics of athletes. However, no study has examined whether plyometric training incorporated with augmented feedback to landing skills would have similar effects. Therefore, the purpose of this research was to examine the effects of six-week plyometric training incorporated with augmented feedback to landing skills. According to the purpose, two study objectives were developed: 1) to examine whether plyometric training was effective in influencing ground reaction forces, landing performance, isokinetic muscle strength, vertical jump height, and anaerobic power and 2) to examine whether extra augmented feedback given was effective in influencing ground reaction forces, landing performance, isokinetic muscle strength, vertical jump height, and anaerobic power.
The current research was a prospective, double-blind and randomized controlled trial. There were 21 college-level male adults recruited for the research and randomized allocated to PYT+AF and PYT groups. Participants received their major measurements during pre-, mid-, and post-training testing sessions. The major measurements included variables of kinetic and kinematic during landing from a countermovement jump, landing performance, muscle performance, and sports performance. The research used force platform, motion analysis system, isokinetic testing system, jump-and-reach system, and Margaria power test to examine the variables. The participants were required to perform countermovement jump for the measurement of kinetic and kinematic variables as well as the measurement of vertical jump height. Isokinetic testing system was used to examine the muscle strength of lower extremities while Margaria power test was used to examine the anaerobic power of the participants. 2×3 ANOVA with repeated measures was used to compare the differences between groups and between different testing sessions. Friedman test would be used instead if the variables were not normally distributed. All statistical analyses were calculated using SAS 9.2. The significant level was set as α=.05 while the power was set at 0.8.
The results of the current research were: 1) six-week plyometric training incorporated with augmented feedback significantly improved vGRF, growth gradient, landing time, and degree of knee flexion angle during jump-landing task when impulse remained unchanged, 2) the training significantly improved eccentric muscle strength but not concentric muscle strength and muscle torque steadiness, and 3) the training significantly improved vertical jump height as well as power and was independent of the groups the participants were allocated in.
These results concluded that plyometric training incorporated with augmented feedback was effective in improving the jumping and landing performance simultaneously. Nevertheless, the retention effect of the training was unknown as well as its effect on the reduction of injury rates. This was the first research that examined the effect of plyometric training on ground reaction forces, the results suggested that ground reaction forces might increase after training. If additional augmented feedback was given, it could minimize the magnitude of impact forces. As more and more coaches and athletes adopted plyometric training into their training regime, augmented feedback could prevent the negative effects that brought by plyometric training. Future researches and coaches should add on augmented feedback into the plyometric training protocols so as to reduce the potential risks.
|Appears in Collections:||物理治療學系所|
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