Mehta Ranjana K, Cavuoto Lora Anne
Texas A&M University, College Station.
University at Buffalo, New York.
Hum Factors. 2017 Aug;59(5):722-733. doi: 10.1177/0018720817695194. Epub 2017 Mar 7.
The objective of the current study was to determine the effect of body mass index (BMI) on fatigability of three different muscle groups at four different work intensities.
Forty-nine normal-weight, 50 overweight, and 43 obese adults (32.1 ± 9.2 years; 50% males) performed fatiguing handgrip, shoulder flexion, and trunk extension exertions at 20%, 40%, 60%, and 80% of the associated maximum voluntary contractions.
Obese adults demonstrated 22% to 30% shorter endurance times than normal-weight adults, but this was only observed at lower intensities and with larger and more postural muscles of the shoulder and low back. Strength and fatigue-related strength loss remained comparable across BMI groups in both males and females in these task-specific conditions. Obesity was associated with faster progression in perception of effort at low-intensity shoulder and trunk exertions. While males were stronger than females across all muscle groups, females exhibited greater shoulder fatigue resistance than males at lower intensity levels.
Findings indicate that the relationship between obesity and fatigability is task dependent.
These findings provide initial evidence on the impact of obesity on worker capacity. Future work that extends the current investigation to include more occupationally relevant scenarios are needed to facilitate occupational task (re)design and assessment practices, such that altered work capacities of two-thirds of the working population are accommodated.
本研究的目的是确定体重指数（BMI）对四个不同工作强度下三种不同肌肉群疲劳性的影响。
49名体重正常、50名超重和43名肥胖成年人（32.1±9.2岁；50%为男性）在相关最大自主收缩的20%、40%、60%和80%强度下进行疲劳性握力、肩部屈曲和躯干伸展运动。
肥胖成年人的耐力时间比体重正常的成年人短22%至30%，但这仅在较低强度以及肩部和下背部较大且更多参与姿势维持的肌肉中观察到。在这些特定任务条件下，男性和女性的BMI组之间力量以及与疲劳相关的力量损失仍相当。肥胖与低强度肩部和躯干运动时用力感知的更快进展相关。虽然在所有肌肉群中男性比女性更强壮，但在较低强度水平下女性比男性表现出更大的肩部抗疲劳能力。
研究结果表明肥胖与疲劳性之间的关系取决于任务。
这些发现为肥胖对工作能力的影响提供了初步证据。需要开展进一步工作，将当前研究扩展到包括更多与职业相关的场景，以促进职业任务（重新）设计和评估实践，从而适应三分之二工作人群改变的工作能力。
