title: Influence of Manual Labor at Work on Muscular Fitness and Its Relationship With Work Performance.
abstract: The present study examined the influence of workplace manual labor on measures of muscular fitness, with a secondary aim to investigate the relationship between muscular fitness and work performance in blue-collar (BC) workers.
  
  
  
  Leg extension isokinetic strength at slow and fast velocities, hamstring and hip-flexor flexibility, and low back muscular endurance were examined in young and older BC workers and white-collar (WC) controls, while work performance was examined in the BC cohort.
  
  
  
  There were no differences in muscular fitness variables between BC and WC groups; however, the older men had lower low back muscular endurance (-43.0%) and strength at slow (-9.4%) and fast (-12.7%) velocities. Work performance was associated with strength at fast velocities (r = 0.633) in the older BC workers.
  
  
  
  Leg strength may influence work performance, with higher velocities becoming more important in older workers.
authors.affiliation: Neuromuscular Research Laboratory, Department of Exercise and Sport Science (Dr Ryan), Allied Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (Dr Ryan), Neuromuscular Research Laboratory, Health, Physical Education and Recreation Department, Utah State University, Logan, Utah (Dr Thompson), and Department of Health Sciences, Furman University, Greenville, South Carolina (Dr Sobolewski).
authors.forename: Eric D
authors.initials: ED
authors.lastname: Ryan
authors.forename: Brennan J
authors.initials: BJ
authors.lastname: Thompson
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Sobolewski
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D015444:Exercise; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D010807:Physical Endurance; D010809:Physical Fitness; D016059:Range of Motion, Articular; D000066477:Work Performance; D055815:Young Adult