Locomotor-respiratory coupling during axillary crutch ambulation.
OBJECTIVE
To test the hypotheses that locomotor-respiratory coupling occurs in humans using axillary crutches in a swing-through ambulation pattern and that expiration occurs during crutch-stance phase during locomotor-respiratory coupling.


METHODS
Eighteen able-bodied persons were trained in one-footed swing-through gait with axillary crutches. Then, as subjects walked at "somewhat hard" speeds (Borg) on a motorized treadmill for 5 min, we recorded signals from a crutch pressure switch and a mouthpiece-mounted thermocouple. Coupling was defined as being present when the onset of inspiration varied by < or = 5% with respect to the onset of the crutch gait cycle for a minimum of 10 consecutive gait cycles and when there was no drift on a raster plot of the respiratory phases relative to the onset of the gait cycle.


RESULTS
Ten (56%) of the 18 subjects exhibited locomotor-respiratory coupling on 1-4 occasions each, with episodes lasting 11.3-148 sec. In 17 (89%) of the 19 episodes of 1:1 locomotor-respiratory coupling, expiration occurred during the crutch-stance phase of the gait cycle and inspiration occurred during crutch swing.


CONCLUSIONS
Transient 1:1 locomotor-respiratory coupling occurs in many able-bodied subjects ambulating with axillary crutches and a swing-through gait. Expiration is most often associated with the crutch-stance phase of the gait cycle. This study may have implications for training axillary crutch users.
Hurst
C A
CA
School of Kinesiology, Dalhousie University, Halifax, Nova Scotia, Canada.
Kirby
R L
RL
MacLeod
D A
DA
D000328:Adult; D003446:Crutches; D005080:Exercise Test; D005260:Female; D005684:Gait; D006801:Humans; D008124:Locomotion / Q000502:physiology*; D008297:Male; D013997:Time Factors