Low back loads while walking and carrying: comparing the load carried in one hand or in both hands

Abstract

Carrying a load in one hand (30 kg) resulted in more spine load than splitting the same load between both hands (15 kg). When carrying double the load in both hands (30 kg in each hand vs. 30 kg in one hand), spine load decreased, suggesting merit in balancing load when designing work.

Too Fit To Fracture: outcomes of a Delphi consensus process on physical activity and exercise recommendations for adults with osteoporosis with or without vertebral fractures

“…The torque generated is not dependent only on the mass, but on the moment arm, or the distance from the pivot point to the point where the force is applied. For example, carrying a load out in front with elbows bent 90°, or in one hand at the side of the body imposes a greater compressive load on the spine than dividing the weight between two hands and carrying it at one's sides, close to the body (Box 4) [24,25]. In the thoracic spine, holding 11 lbs (5 kg) in each hand with elbows flexed to 90° has been reported to increase the compressive loads at T8 and T12, ~ 3.0 and 3.5 times that of standing, respectively [22].…”

“…Bending forward will also increase the compressive and shear loads on the spine (24). Therefore, in theory, a person with a history of spine fractures might be able to hold a given weight safely if the weight is divided between hands held at sides, but not if it is held in front of the body, or while bending forward with it.…”

Gait analysis parameters of healthy human subjects with asymmetric loads

“…Unilateral load carriage is known to be more hazardous to the musculoskeletal system than bilateral loading (DeVita et al (1991), Fowler et al (2006 or McGill et al (2013)), leading finally to many disorders of which the most common is low back pain. We found that walking with asymmetric loads from 0 to 11.33 kg, in 2.26 kg increments, do not affect the COR, even though the two areas defined under GRF curves tend to increase with the increase in load.…”

How does the way a weight is carried affect spinal loads?

“…Several sophisticated analytical models exist that allow estimation of the spinal load when carrying a weight (McGill and Norman 1986;Cholewicki and McGill 1994;Stokes and Gardner-Morse 1995;Granata and Marras 2000;De Zee et al 2007). McGill, Marshall, andAndersen (2013) estimated spinal loads when carrying weights in one hand and in both hands. They found that carrying a weight in one hand resulted in substantially more compressive load on the low back than when the weight was split evenly between both hands.…”