Comparison of anthropometry to DXA: a new prediction equation for men.

OBJECTIVE: This study compared three professionally recommended anthropometric body composition prediction equations for men to dual energy X-ray absorptiometry (DXA), and then developed an updated equation, DXA Criterion (DC) from DXA. DESIGN: Cross-sectional. SETTING: Exercise Physiology Lab. University of Missouri-Columbia, USA. SUBJECTS: A total of 160 men aged 18-62 y old. INTERVENTIONS: Percent body fat (%BF) by anthropometry was compared to DXA on the same day. RESULTS: Although %BF was significantly correlated (r=0.923-0.942) (P<0.01) with DXA for all three equations, each equation underestimated %BF (range=3.1-3.3%) (P<0.01) compared to DXA. The following DC equation for men was created: %BF=0.465+0.180(Sigma7SF)-0.0002406(Sigma7SF)(2)+0.06619(age); (Sigma7SF=sum of chest, midaxillary, triceps, subscapular, abdomen, suprailiac, thigh; age=years). The predicted residual sum of squares (PRESS) R(2) was high (0.90) and the PRESS standard error of estimates was excellent (2.2% at the mean) for the DC equation when applied to our sample of 160 men. CONCLUSIONS: The currently recommended anthropometric equations for men underestimate %BF compared to DXA. The DC equation yields a more accurate estimation of %BF in men aged 18-62 y old. The results from this study support the need for the current %BF standards and norms for men to be adjusted upward.

Comparison of perceived comfort differences between standard and experimental load carriage systems.

The current popularity of backpack-type load carriage systems (LCS) by students has precipitated a prevalence of postural abnormalities and pain. This study compared subjective perceptual comfort in standard and vertically loaded LCSs. Sixteen females ages 18-23 years rated their personal LCSs for perceived shoulder, neck, and lower back comfort and for overall comfort, each day for two weeks using 100 mm visual analogue scales (VAS). Each scale contained polar extremities of 'very comfortable' to 'very uncomfortable' and a vertical mark placed on the 100 mm line by the participants indicated their perception of comfort. Following two weeks, participants were given LCSs that distributed the weight vertically and were asked to rate the system in the same way for an additional two-week period. Statistical analysis revealed significant differences in shoulder (p=0.015), neck (p=0.005), and lower back (p=0.036) comfort and overall comfort (p=0.001) between the participants' personal LCSs and the experimental LCS. In conclusion, vertical load placement may redistribute the load in a manner that reduces symptoms of selected anatomical discomfort.