Effect of arm swinging on lumbar spine and hip joint forces
Introduction
Walking is one of the most important activities in daily life and exposes the spine to cyclic loading conditions, with an average load approximately equal to 170% the one observed in the standing position (Rohlmann et al., 2014). The motion of the arms in opposite direction to the lower limbs as well as the trunk axial rotation are distinctive features of the human gait. Arm swing (AS) improves the dynamic body stability (Nakakubo et al., 2014, Ortega et al., 2008, Punt et al., 2015) by counterbalancing the angular momentum produced by legs (Elftman, 1939, Hinrichs, 1990, Park, 2008). Additionally, it reduces the vertical displacement of the centre of mass (Hinrichs, 1990, Murray et al., 1967, Umberger, 2008) and the free vertical moment generated at the contact between the foot and the ground (Angelini et al., 2016, Li et al., 2001, Witte et al., 1991).
Current studies on the influence of arm movement during level walking were mainly focused on the investigation of metabolic variables (Umberger, 2008), force plate data (Angelini et al., 2016, Li et al., 2001), gait parameters (Angelini et al., 2016) or lower limb kinematics and kinetics (Umberger, 2008). To our best knowledge, only Callaghan et al. (1999) examined the AS effects on low back joint forces during walking, yet considering only two arm conditions (i.e., free AS or arms crossed across the chest). In vivo studies on spinal loads in patients with a vertebral body replacement (VBR) showed that the arm position could affect the load transfer mechanism in sitting and standing (Dreischarf et al., 2010, Zander et al., 2015).
The present study aimed to investigate the effect of different arm positions and AS amplitudes on the kinematics and on joint reaction forces on the hip and on the upper and lower lumbar spine. For this purpose, the research was divided into two steps: an experimental campaign for acquiring human motion data during barefoot level walking, and a second step focused on musculoskeletal simulations. A statistical analysis was performed to investigate the significance of arm position and AS amplitude on several selected output quantities, including the range of motion (RoM) at several joints and the joint reaction forces (JRFs). Experimental data from instrumented implants were used to validate the musculoskeletal model.
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Study participants
Six healthy male volunteers (Group A) and five patients with instrumented hip implant (Group B) were considered (Table 1). In Group A, only subjects with no current or previous back or hip pain and musculoskeletal disorders were included. The patients of Group B were in good physical condition to perform all investigated activities without limitations. Both, subjects of Group A and patients of Group B received a physical exam by a clinician to exclude the presence of spine deformities.
The
Model validation
As a first step in the analysis of results, hip JRFs resulting from numerical simulations and recorded from instrumented implants were compared, with the aim of validating the model. For instance, Fig. 3A shows the resultant hip force (Fres) and the three force components predicted by the musculoskeletal model and measured in vivo for the patient H2R during walking with a NAS. They are expressed in the femur coordinate reference system of the implant. Fres showed two typical peak values at
Discussion
In order to investigate how arm position or AS amplitude could affect the hip and spine kinematics and JRFs during level walking, motion data of both, six asymptomatic subjects and five patients with instrumented hip implant were captured in Vicon system. A total of 180 musculoskeletal simulations for Group A were run to compare the RoMs and the JRFs during the five walking tasks, including three different AS amplitudes and two different arm positions.
Acknowledgments
This study was financially supported by the Bundesinstitut für Sportwissenschaften, BiSp (MiSpEx - Network).
Conflict of interest
There are no conflicts of interest.
References (50)
- et al.
Influence of lumbar spine rhythms and intra-abdominal pressure on spinal loads and trunk muscle forces during upper body inclination
Med. Eng. Phys.
(2016) - et al.
Effect of skin movement artifact on knee kinematics during gait and cutting motions measured in vivo
Gait & Post.
(2006) - et al.
Low back three-dimensional joint forces, kinematics, and kinetics during walking
Clin. Biomech.
(1999) - et al.
A physiologically based criterion of muscle force prediction in locomotion
J. Biomech.
(1981) - et al.
Total hip joint prosthesis for in vivo measurement of forces and moments
Med. Eng. Phys.
(2010) - et al.
A generic detailed rigid-body lumbar spine model
J. Biomech.
(2007) - et al.
Advanced age and the mechanics of uphill walking: a joint-level, inverse dynamic analysis
Gait & Post.
(2014) - et al.
Musculo-skeletal loading conditions at the hip during walking and stair climbing
J. Biomech.
(2001) Scaling gait data to body size
Gait & Post.
(1996)- et al.
Algorithms to determine event timing during normal walking using kinematic data
J. Biomech.
(2000)