Elsevier

Journal of Biomechanics

Volume 48, Issue 15, 26 November 2015, Pages 4059-4064
Journal of Biomechanics

Effects of lower-limb muscular fatigue on stair gait

https://doi.org/10.1016/j.jbiomech.2015.10.004Get rights and content

Abstract

The objective of the present study was to determine the effects of lower-limb muscular fatigue on stair gait. Twelve healthy young male adults between 20 and 30 years old participated in the experiment. There were two experimental sessions corresponding to a no fatigue condition and a lower-limb muscular fatigue condition, respectively. Lower-limb muscular fatigue was induced using repetitive lower-limb pushing exertions. Both ascent and descent were studied. Stair gait was assessed by lower-limb joints and trunk kinematics, and postural stability measures. It was found that lower-limb muscular fatigue compromised stair gait during descent, but did not make any difference during ascent. These findings highlighted the importance of minimizing exposures to lower-limb muscular fatigue during descent in stair accident prevention.

Introduction

Stair negotiation, which is one of the most demanding locomotor tasks, is very common in daily life. Stairs are considered as one of the most hazardous locations in the workplace and at home (Cayless, 2001), as a large proportion of accidents and injuries happen when people ascend or descend stairs. The most common accidents during stair negotiation are fall accidents. Around one out of ten fall accidents take place on staircases (Startzell et al., 2000; Svänstörm, 1974). Gait abnormality is a key risk factor for falls (Rubenstein, 2006). Therefore in order to prevent stair falls, there is a need to better understand stair gait. Some researchers reported the kinematic and kinetic differences between stair negotiation and level walking (Costigan et al., 2002, Nadeau et al., 2003). It was generally found that stair gait was associated with larger lower-limb joint range of motion and larger joint moments compared to level walking. Some researchers studied age-related differences in stair gait and attempted to use their findings to explain the higher risk of falls in older adults during stair negotiation (Bosse et al., 2012, Mian et al., 2007, Novak and Brouwer, 2011). For instance, Bosse et al. (2012) found that older adults showed a lower ankle and knee joint angular impulse before the initiation of the single support phase. Based on this finding, they further suggested that decreased leg-extensor muscular output with aging is the cause of higher risk of falls in older adults during descent.

Many studies presented that safe stair negotiation was dependent on adequate lower-limb muscle strength (Karamanidis and Arampatzis, 2011, Reeves et al., 2008). Muscular fatigue leads to decreased muscle strength (Vøllestad, 1997), which could be a risk factor compromising stair gait. The effects of lower-limb muscular fatigue on gait have been investigated in previous work (Longpré et al., 2013). In general, lower-limb muscular fatigue was found to have adverse effects on gait. However, in previous studies, gait was mainly assessed during level walking. The effects of lower-limb muscular fatigue on stair gait are seldom studied. A recent study has evaluated the effects of muscular fatigue of the triceps surae and quadriceps muscles in stepping down in ongoing gait (Barbieri et al., 2014). However, in this study, only localized muscular fatigue at the ankle and knee was examined. Multi-joint movements are more common than single-joint movements in both daily activities and occupational settings, and mobility of one joint is typically dependent on the position of an adjacent joint (aka. two-joint muscle effect) (Chaffin et al., 1996). Thus, applying localized muscular fatigue protocols to a single lower-limb joint is limited in replicating the muscular fatigue in real life.

The objective of the present study was to determine the effects of lower-limb muscular fatigue on stair gait during both ascent and descent. Gait analysis is typically conducted from kinematic and kinetic perspectives (Prince et al., 1997). In the present study, lower limb joints and trunk kinematics were used to characterize stair gait. Kinetic analysis was not undertaken here due to the lack of necessary measuring device in the experiment. Besides, stair gait was also assessed by postural stability measures as understanding how humans maintain postural stability is essential for predicting the likelihood of falls (Hsiao and Simeonov, 2001, Rubenstein, 2006). In order to replicate the fatigue in real life, the examined lower-limb muscular fatigue was multi-joint muscular fatigue. It was hypothesized that lower-limb muscular fatigue would compromise lower limb joints and trunk kinematics, and lead to decreased postural stability, during both ascent and descent.

Section snippets

Participants

Twelve healthy young male adults between 20 and 30 years old participated in the experiment. The mean±SD of the age, height and body weight of the participants are 24.0±1.4 years, 174.7±6.2 cm, and 68.3±7.9 kg, respectively. All the participants self-reported to have no musculoskeletal injuries in the past 12 months. They all also self-reported to prefer using their right foot to kick a soccer ball, and such information was used to determine their foot dominance. Informed consent which was

Results

Lower-limb muscular fatigue did not affect lower-limb joints kinematics during ascent (Table 2). However, lower-limb joints kinematics during descent became significantly different between the no fatigue and fatigue conditions (Table 3). Specifically, smaller ankle plantarflexion, smaller knee flexion, and smaller hip flexion were observed at the moment of dominant foot contact of descent in the fatigue condition versus no fatigue condition. At the moment of non-dominant foot release of

Discussion

Previous research has reported that lower-limb muscular fatigue affected gait during level walking (Barbieri et al., 2013) and obstacle negotiation (Hatton et al., 2013). Stair ascent raises the body to a higher level. Thus, stair ascent is a more challenging locomotor task and involves larger energy consumption compared to level walking and obstacle negotiation. Meanwhile, muscular fatigue is associated with reduced energy generation capacity. Based on these arguments, lower-limb muscular

Conflict of interest

The author does not have financial or personal relationship with other persons or organizations that might inappropriately influence the work presented therein.

Acknowledgements

This work is supported in part by the Natural Science Foundation of Guangdong Province of China (Project # 2015A030313553).

References (30)

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