Optimal spinal strength normalization factors among male railroad workers

Tom G. Mayer, Robert J. Gatchel, Janice Keeley, Holly Mayer

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


In spite of increasing interest in techniques and devices for quantifying trunk strength anti lifting capacity, relatively little research has been determine optimal normalizing factors for strength-The isolation of tits ideal factors is a critical prerequisite for comparison of patient data to expected physical capacities in the uninjured population. In the present study, 160 incumbent railroad workers from four heavy laboring jobs were tested for isokinetic trunk strength and Igm bar/cervical isokinetic lifting capacity as part of a study to establish normative data (Union Pacific RH, Omaha, NE). Three variables relating height and weight were studied to determine optimal normalisation: actual body weight (BW), ideal weight (IW) and adjusted weight l AWI. "IW" is actually a height/weight variable based on a weight control chart specifying ideal weights for given heights and genders. "AW" represents the lesser of BW or IW. Subjects were tasted for Isokinetic trunk extension/flexion for lumbar (floar-to-knuckle) and cervical (knuckle-to-shoulder) lifts. Results demonstrated that the isolated trunk strength tests showed the best correlation coefficients with BW for flexion-extension work at 60 and ISO per sec. Moreover, the correlation coefficients between the lumbar isokinetic lifting peak force measures and BW ware high (ranging 0.49-0.67, P < 0.001), with much lower correlations for AW or IW. By contrast, cervical correlations between Liftask peak force and the height/weight variables were all lower, and were also belter for AW than for BW or IW (ranging D.37-D.50I. It appears that body weight is the best normalizing factor for isokinetic trunk flexor/extensor strength and lumbar (floor-to-knuckle) lifting. Adjusted weight is a better normalizing factor for cervical (knuckle-to-shoulder) isokinetic lifting.

Original languageEnglish
Pages (from-to)239-244
Number of pages6
Issue number2
StatePublished - Feb 1993


  • Isokinetic
  • Lifting capacity
  • Normalizing factors
  • Occupational sample
  • Peak force
  • Trunk strength
  • Work


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