1Department of Health, Exercise and Sport Sciences, University of New Mexico, Albuquerque, New Mexico; 2Human Performance Laboratory, Department of Health and Exercise Science, Truman State University, Kirksville, Missouri; 3Department of Physiology, A. T. Still University of Health Sciences, Kirksville, Missouri; 4Department of Kinesiology, Northeast Lakeview College, Universal City, Texas; and 5Exercise and Sports Nutrition Laboratory, Department of Health and Kinesiology, Texas A&M University, College Station, Texas.
J Strength Cond Res. 2014 May;28(5):1246-54. doi: 10.1519/JSC.0000000000000389.
The factors that best account for differences in strength across all types of exercise, body types, and training histories are not well understood. The purpose of this study was to assess the effects of strength level and body composition on upper- and lower-body work capacity in adult men. From a cohort of 295 adult men (25.6 ± 7.5 years, 178 ± 8 cm, 85.2 ± 15 kg), low-strength (LS, n = 72) and high-strength (HS, n = 66) samples were selected based on 1 repetition maximum (1RM) bench press (BP) and leg strength (LP) values. Work capacity for each exercise was determined from the product of repetition weight (80% 1RM) and maximum repetitions-to-fatigue (RTF). Body composition was measured using dual-energy x-ray absorptiometry. The HS group was significantly greater than the LS group in total body mass and fat-free mass but not in age, height, fat mass, or %fat. Low-strength and HS groups were not significantly different (p > 0.05) in RTF for either BP (8.7 ± 3.1 vs. 8.3 ± 1.9 reps, respectively) or LP (15.6 ± 7.6 vs. 17.0 ± 6.3 reps, respectively), making the ratio of RTF for BP vs. LP nonsignificant (LS = 2.0 ± 1.0; HS = 2.2 ± 0.9). The HS group produced significantly greater (p < 0.001) absolute and relative work capacities for both BP and LP compared with the LS group. Repetitions-to-fatigue had a greater influence on BP (r2 = 0.74) and LP (r2 = 0.85) work capacities in the LS group than did RepWt (r2 = 0.07 and 0.28, respectively). In the HS group, RTF (r2 = 0.79) had a greater influence than RepWt (r2 = 0.10) on BP work capacity, whereas the 2 components were more similar for LP work capacity (r2 = 0.64 and 0.47, respectively). When evaluated at the same %1RM, muscular endurance is similar across divergent strength levels meaning that work capacity (load × reps) will be greater for HS individuals. Controlling for the influence of body composition variables (e.g., fat or fat-free mass) does not eliminate the difference in work capacity between strength groups suggesting that other factors are accounting for strength expression. Prescribing repetitions against a fixed relative load is largely dependent on exercise type and must be considered by strength and conditioning professionals.
目前，人们对导致不同类型运动、体型和训练史的力量差异的因素还不太了解。本研究旨在评估力量水平和身体成分对上、下身工作能力的影响。从 295 名成年男性（25.6 ± 7.5 岁，178 ± 8 cm，85.2 ± 15 kg）中，根据 1 次最大重复（1RM）卧推（BP）和腿部力量（LP）值选择低强度（LS）和高强度（HS）样本。每个练习的工作能力是通过重复重量（80%1RM）和最大重复至疲劳（RTF）的乘积来确定的。身体成分使用双能 X 射线吸收法进行测量。HS 组的全身质量和去脂体重明显大于 LS 组，但年龄、身高、脂肪质量或%脂肪无差异。LS 和 HS 组的 BP（分别为 8.7 ± 3.1 和 8.3 ± 1.9 次）或 LP（分别为 15.6 ± 7.6 和 17.0 ± 6.3 次）的 RTF 没有显著差异（p > 0.05），因此 BP 与 LP 的 RTF 比值无显著性差异（LS = 2.0 ± 1.0；HS = 2.2 ± 0.9）。与 LS 组相比，HS 组在 BP 和 LP 方面产生的绝对和相对工作能力明显更高（p < 0.001）。在 LS 组中，RTF（r2 = 0.74）和 RepWt（r2 = 0.07 和 0.28）对 BP 和 LP 的工作能力的影响更大。在 HS 组中，RTF（r2 = 0.79）对 BP 工作能力的影响大于 RepWt（r2 = 0.10），而 LP 工作能力的两个因素更为相似（r2 = 0.64 和 0.47）。当以相同的%1RM 进行评估时，不同力量水平的肌肉耐力相似，这意味着 HS 个体的工作能力（负荷×重复次数）将更大。控制身体成分变量（如脂肪或去脂体重）的影响并不能消除力量组之间的工作能力差异，这表明其他因素正在解释力量表现。根据固定相对负荷规定重复次数在很大程度上取决于运动类型，必须由力量和体能专业人员考虑。
