Central adiposity and mechanical, perceptual and physiological loading during long duration, repetitive lifting. (December 2018)

• Record Type: Journal Article
• Authors: Pryce, Robert; Kriellaars, Dean
• Is Part Of: Clinical biomechanics. Volume 60(2018)
• Page Start: 170
• Page End: 176
• Publication Date: 2018-12
• Subjects: Obesity -- Materials handling -- Exertion -- Heart rate; Biomechanics -- Periodicals; Osteopathic medicine -- Periodicals; Biomechanics -- Periodicals; Osteopathic Medicine -- Periodicals; 612.76
• DOI: 10.1016/j.clinbiomech.2018.10.011
• Languages: English
• ISSNs: 0268-0033

Abstract

Abstract: Background: There is an absence of information regarding the impact of central adiposity on loading during long duration, repetitive lifting, and very limited information of the impact of elevated body mass on mechanical loading of the lumbar spine. This information is important in evaluation of the validity of injury prevention standards and interventional approaches in this segment of the population. Methods: This study evaluated the mechanical, physiological, and perceptual loading during repetitive lifting in participants with central adiposity compared to participants with normal body mass index. Videography, accelerometry, heart rate and perceived exertion measures were used to examine alternations in kinematic, kinetic, and exertional parameters during a 1-hour lifting task (3 × 20-min sets; 4 lifts/min; self-selected mass). Findings: Low back torque [+69.1 (11.5) Nm], compressive force [+1036.6 (153.6) N] and heart rate [+7.0 (3.5)%] were substantially elevated in participants with central adiposity, however perceived exertion and self-selected mass did not differ between groups. With central adiposity a compensatory mechanism was observed, involving a reduction in trunk vertical displacement [−5.8 (1.9) cm], hip flexion [−6.4 (3.1) deg] and lower-trunk flexion [−10.0 (2.7) deg], which attenuated expected increases to work [9.8 (2.3)%], power [9.5 (4.0)%] and physiological effort. Interpretation: While mechanical loading increases secondary to elevated body mass are expected, these results provide new insight into origins of such increases for individuals with a central adiposity somatotype. The differences in mechanical, physiological and perceived loading support provision of individual-specific injury prevention strategies, as well as revision of existing mechanical- and physiological-based ergonomic standards. Highlights: Central adiposity increased mechanical and physiological loading during lifting. Central adiposity did not increase perceived exertion during lifting. The moment arm (and torque) of external loads were increased in central adiposity. Movement strategy in central adiposity may change to minimize mechanical work. Injury prevention strategies for lifting should account for these differences.