No abstract

<p>Background:  Arm swing during human gait is associated with contractions of upper limb muscles, which have been examined rarely.</p><p>Aim: This study aims to identify basic temporal patterns of upper limb muscle activation during walking conditions involving different modes of arm swing.</p><p>Method: Twenty volunteers were examined during (a) normal forward walking, (b) walking with immobilized arms, (c) walking while carrying loads in one or in both hands. Electromyographic (EMG) data were collected for the trapezius (TRAP), anterior (AD) and posterior deltoid (PD), biceps (BIC), triceps (TRI), latissimus dorsi (LD) and lumbar erector spinae (ES) muscles.</p><p>Results: Principal components analyses identified two basic patterns of muscle activation that remained stable across gait conditions. Some rhythmical EMG signals of arm and shoulder muscles (TRAP, PD, TRI, LD) persisted during walking with immobilized arms, indicating coupled activation of leg and arm muscles. Carrying a load in one hand resulted in stronger ipsilateral EMG activity (TRAP, AD, PD, BIC, TRI) than splitting the same load between both hands.</p><p>Interpretation: Although the amount of upper limb muscle activity varies markedly between different conditions of human walking (with/without arm sing; with/without load carriage), basic temporal activation patterns remain stable, indicating a common motor control strategy.</p><em><br clear="all" /> </em>

<p>Background: Arm swing is deliberately emphasized during power walking, a popular aerobic fitness exercise. Electromyographic (EMG) activation curves of arm and shoulder muscles during power walking have not yet been examined. Aim: To describe the amount and pattern of EMG activity of upper limb muscles during power walking. Data are compared to normal walking and jogging. Method:  Twenty volunteers were examined on a treadmill at 6 km/h during (a) normal walking, (b) power walking, (c) jogging. EMG data were collected for the trapezius (TRAP), anterior (AD) and posterior deltoid (PD), biceps (BIC), triceps (TRI), latissimus dorsi (LD) and erector spinae (ES) muscles. Results:  Activity of four muscles (AD, BIC, PD, TRAP) was three- to fivefold stronger during power walking than normal walking. Smaller significant increases involved the TRI, LD and ES. Two muscles (AD, TRAP) were more active during power walking than running. Normal walking and power walking involved similar EMG patterns of PD, LD, ES, while EMG patterns of running and walking differed. Interpretation: Emphasizing arm swing during power walking triples the EMG activity of upper limb muscles, compared to normal walking. Similar basic temporal muscle activation patterns in both modes of walking indicate a common underlying motor program. </p>

Arm swing during human gait has both passive and active components. The chapter presents a study conducted with normal subjects using electromyography (EMG) to describe patterns of arm and shoulder muscle activity in different gait conditions. These included normal forward walking, walking with immobilized arms, backward walking, power walking with accentuated arm swing, running, and load carriage. Complementary kinematic data are presented, too. Rhythmic muscle activity persists to some extent when both arms are immobilized during walking. Forward and backward walking involve dissimilar patterns of muscle activity, although the limb movements are very similar in both conditions. Likewise, power walking and running are characterized by different curves of EMG activity. Unimanual load carriage during walking affects muscle activities of both the loaded and the non-loaded arm. Research on normal arm swing provides a basis for clinical investigations of gait disorders.