Postural adjustments while standing with two types of loaded backpack ∗

The effect of training on lumbar spine posture and intervertebral disc degeneration in active-duty Marines

“…These data suggest that when external load is applied the LS becomes more flexed, which is in agreement with previous reports (Al-Khabbaz, Shimada, and Hasegawa 2008, Attwells et al 2006, Bust andMcCabe 2005). This increase in lumbar flexion may be a compensatory response used to reorient the center of mass of the system (body + loaded pack) over the feet (Bloon andWoodhull-McNeal 1987, Knapik, Harman, andReynolds 1996); however, this idea needs to be tested explicitly. In this study, LS flexion was on average 72.74±5.04° (or 17.26° anterior to vertical) when carrying a load of approximately 25% BW.…”

A biomechanical model via Kane’s equation – solving trunk motion with load carriage

“…Table 1 shows that without any load, children aged from 14 months to 13 years are already in the forward lean position, which is in contrast with adults, who are in the backward lean position when carrying no load. Furthermore, by comparing the results of children and adults, it seems that children have to lean forward while carrying backpack load, regardless of its percentage of the body weight, whereas adults only lean forward when the load increases to 30% of the body weight when walking (Goh et al, 1998) and 27% of body weight when standing (Bloom and Woodhull-McNeal, 1987), which shows that the load condition is heavy for adults. Thus if these load conditions are heavy for adults and they have to lean forward to counterbalance the load at the back of their bodies, then carrying loads of 10%, 15% and 20% of the body weight will be heavier for children because at these load conditions, they also tend to walk with a forward flexion.…”

“…There are articles that have reported on the effects of carrying backpack loads on trunk inclination in adults (Goh et al, 1998;Knapik et al, 1996;Al-Khabbaz et al, 2008;Bloom and Woodhull-McNeal, 1987) and children (Garciaguirre et al, 2007;Rahman et al, 2009;Hong and Brueggemann, 2000;Hong and Cheung, 2003;Li and Hong, 2001;Shasmin et al, 2007;Pascoe et al, 1997). However, studies on the effects of carrying backpack load on adults have been done while walking (Goh et al, 1998) and also while standing (Al-Khabbaz et al, 2008;Bloom and Woodhull-McNeal, 1987). Different methods of carrying backpack load have also been used to investigate the inclination of the trunk, including carrying the load at the front, at the back and at the side of the body, carrying a backpack with one or two straps and carrying a frame backpack.…”

“…The results of the changes in trunk posture for all three conditions of backpack load showed that the trunk inclined backward -3.37º, -3.02º and -3.90º during 10%, 15% and 20% of the body weight load conditions, respectively. Bloom and Woodhull-McNeal, (1987) examined the changes in body posture induced by two types of frame backpack: the internal-frame pack and the external-frame pack on nine women and seven men between 19 -25 years old. The study examined how carrying each pack with a load of an average of 27% of body weight changed the body posture compared with the typical standing posture.…”

Kinematic and electromyographic analysis of school children gait with and without load in the backpack

“…When the backpack with excessive load is transported, the center of mass is pulled to posterior direction. In the attempt to return to the appropriate position, similar to no load condition, the trunk moves to the opposite side tilting then forward, such adjustment helps the body minimize energy costs and increase the efficiency of the gait when carrying weight (Bloom and Woolhull-McNeal, 1987;Hong and Cheung, 2003).…”