臺灣一般健康族群之肌力常模

Abstract

臺灣一般健康族群之肌力常模 目的： 隨著年齡變化，肌肉質量會逐漸減少，已是近來老年醫學中重要的發現及人類必經的生理變化。肌少症已知會影響老年人的生活品質及預後。 然而肌肉量不完全等於肌力，肌肉量足夠，未必具有相當的肌力表現。過去臺灣僅有少數論文研究握力或下肢肌力常模，並沒有涵括年輕族群的全年齡層肌力變化調查，亦沒有同步進行上下肢肌力測試的研究。故本研究主要目的為調查臺灣一般健康族群之肌力，並建立一套可供信任的常模，提供未來慢性病族群參照。 方法： 此研究屬於橫斷式研究(a cross-sectional study)，於2018年6月至2019年6月一年間，自願在臺北市好心肝健檢中心及臺大醫院老年醫學部受檢的20歲以上、小於80歲之受試者完成全身檢查後，經協同主持人、或其他醫護人員口頭介紹，同意參與研究者，將收集測量其三項肌力指標：上肢握力、下肢坐站、單腳站立，並與該次健康檢查中所獲得之結果，以SAS軟體第9.4版，使用共變異數分析(analysis of covariance，ANCOVA)及變異數分析(analysis of variance，ANOVA)、單變量分析(univariate analysis)、多元線性迴歸(multiple linear regression)進行統計。本試驗納入條件為自願於健檢中心安排全身健康檢查之20歲以上臺灣人，初步排除條件則為職業運動員、有肢體殘障、或無法理解實驗指示的受檢者。 結果： 共181位受試者參與研究，包含94位女性及87位男性。以年齡層每10歲分組並分析資料後，女性利手最強握力出現在20-29歲族群，平均為28.2 ± 5.0公斤，而最佳大腿收縮功率(五次坐站5.2 ± 1.1秒)及最長單腳站立時間(30.0 ± 0.0秒)也在20-29歲族群中出現。在男性方面，利手最強握力同樣是在20-29歲，平均為46.7 ± 6.4公斤，最佳大腿收縮功率(五次坐站4.6 ± 0.9秒)及最長單腳站立時間(29.3 ± 1.3秒)亦出現在20-29歲族群裡。經前述方式統計，起初發現性別、年齡、身高、體重、身體質量指數(BMI)、左右手掌長，各部位個別肌肉量、軀幹及全身肌肉總量、相對四肢肌肉量、生物電阻抗儀(BIA)水腫指數、骨質密度、抽菸史、喝酒史及教育程度等因子與利手握力有明顯相關(p<0.05)。對於下肢股四頭肌收縮功率(五次坐站)，年齡、身高、內臟脂肪、BIA水腫指數、骨質密度、運動頻率、運動時間、教育程度為相關因子。左腳站立與年齡、身高、BMI、腰圍、體脂率、內臟脂肪、BIA水腫指數、骨質密度、運動頻率及教育程度相關。而與右腳站立秒數的相關因子初估為年齡、身高、腰圍、體脂率、內臟脂肪、BIA水腫指數、骨質密度、抽菸量、運動頻率、教育程度等。依據以上結果，本研究以多元線性迴歸方式得出此三項肌力的預測公式，最終公式顯示握力與BMI或體重、掌長、四肢相對肌肉量、BIA水腫指數有關；而五次坐站及單腳站立之衰減只與年齡增長有關。 最後，我們並以本研究中調查所得的肌力結果，建立一套肌力Z值常模(與同齡同性別者對照)及兩套T值常模(以20-39歲青年或20-49歲青壯年為參考族群)，可供一般民眾對照。 結論： 這是第一個建立於臺灣一般健康族群之上下肢肌力常模。由此常模可知，許多因子會影響上肢握力、下肢股四頭肌之收縮功率、及平衡能力。憑藉此一健康族群的正常肌力退化，可作為不正常老化或慢性疾病之參考指標。

Muscle Power Norms of an Ostensibly Healthy Taiwanese Population Aims: Sarcopenia and decreased muscle power (dynapenia) are emerging healthy issues related to individual daily function in recent years. There have been some studies exploring the relationship between sarcopenia/muscle power and older age in Taiwan, but there has not been any study exploring muscle power change of both upper and lower limbs among all age groups. The aim of this study is to investigate the muscle power of all age groups in Taiwanese, and to establish a muscle power norm of a healthy Taiwanese population. Methods: This is a cross-sectional study. From 2018 June to 2019 June, all the Taiwanese subjects (aged from 20 years old to 80 years old) undergoing health check-up in Good Liver Medical Examination Center and National Taiwan University Hospital Geriatrics and Gerontology Department were evaluated by serial muscle power examinations including grip strength, five-times sit-to-stand test (5TSTT), and one-leg standing test (OLST), while their physical conditions and questionnaires were assessed by experienced physicians. Those who were professional athletes, physically disabled, or unable to follow instructions were excluded. The participants were divided into several groups, according to age, gender, and certain variables. Basic demographic statistics, analysis of covariance (ANCOVA), analysis of variance (ANOVA), univariate analysis and multiple linear regression model were used to analyze muscle power in both genders of all age groups, with adjustment for other variables. SAS version 9.4 software was used for statistical analysis. Results: A total of 181 participants was enrolled, consisting of 94 females and 87 males. After analyzing their information, we found that the strongest mean grip strength of female is 28.2 ± 5.0 kg with their dominant hand in 20-29-year-old group, while the best mean quadriceps muscle power (5TSTT 5.2 ± 1.1 sec.) and the longest mean one-leg standing time (30.0 ± 0.0 sec.) also appear in 20-29-year-old group. In male population, the strongest mean dominant grip strength is 46.7 ± 6.4 kg in 20-29-year-old group, and their best mean 5TSTT is 4.6 ± 0.9 seconds. The longest mean one-leg standing time is 29.3 ± 1.3 seconds in the age group of 20-29-year-old. Initially we found that gender, age, height, body weight, body mass index (BMI), palm length, individual limb muscle mass, truncal and total muscle mass, relative appendicular lean mass, edema index of bioelectrical impedance analysis (BIA), score of dual energy x-ray absorptiometry (DXA), smoking and drinking habits, and education level are significantly related to dominant handgrip strength (p<0.05). As for lower limb muscle power (5TSTT), it seemed that age, height, visceral fat, BIA edema index, DXA score, exercise frequency, exercise time, and education level are associating factors. Left-leg standing time is related to age, height, BMI, waist circumference, fat percentage, visceral fat, BIA edema index, DXA score, exercise frequency and education level, while right-leg standing time is associated with the aforementioned factors of left-leg standing time and smoking amount, excluding BMI. Finally, multiple linear regression model was used for predicting muscle power norms. BMI (or body weight), palm length, BIA edema index, relative appendicular lean mass are factors affecting dominant handgrip strength, while age is the only effective predicting factor of 5TSTT and OLST. Furthermore, we also established one Z-score muscle power norm of all age groups, and two T-score muscle power norms based on 20-39-year-old and 20-49-year-old reference groups. Conclusions: This is the first muscle power norm of an ostensibly healthy Taiwanese population. Several factors are strongly associated with grip strength, quadriceps power (5TSTT) and balance (OLST). By establishing the norm of healthy adults, we may use this as a reference for abnormally ageing subject or that of a chronically illed patient.