engleski

THE RELATIONSHIP BETWEEN GAIT TRANSITION SPEED AND THE AEROBIC THRESHOLDS FOR WALKING AND RUNNING IN WOMEN

INTRODUCTION Recently, it has been shown that the preferred transition speed between walking and running (PTS) in men does not differ from the aerobic (‘lactate’, or ‘first ventilatory’) thresholds for both, walking (ATw) and running (ATr) gaits. The PTS in men was also found to be related to the aerobic threshold for running, but not for walking. No study has, to our best knowledge, examined those relationships in female subjects. Men and women show no significant gender differences in the PTS, although women, on average, have a lower aerobic capacity (and possibly a lower aerobic threshold) then men. Therefore, the aim of the study was to explore the relationship between ATw, ATr and the PTS in young, healthy women. METHODS Eleven female PE students (19.5+/-0.5y, 169.4+/-5.7cm), performed two incremental treadmill tests to volitional exhaustion, walking in one and running in the other. Gas exchange data (Quark b2, COSMED) were analyzed (V-slope method) in order to determine the first ventilatory (aerobic) threshold for each gait modality. A third treadmill test was also performed in all subjects, in order to determine their individual PTS. RESULTS The ATr had a similar average value (7.34+/-0.5 km/h) as PTS (7.21+/-0.3 km/h, p>.05), while ATw was significantly lower (6.64+/-0.5 km/h, p<.001). The ATw was lower than the PTS and ATr in all subjects. The PTS was significantly correlated with both, ATr (r = 0.77) and ATw (r = 0.72). A high correlation was also present between ATr and ATw (r = 0.80). DISCUSSION AND CONCLUSIONS Sentija and Markovic (2009) in a similar study on male subjects, found almost identical average values for the PTS, ATr and ATw (7.1-7.2 km/h). The PTS in their study was highly correlated to ATr (r=0.82), but not to ATw (r=0.06). Also, the aerobic thresholds for walking and running in men were not correlated (r=0.26, p>.05). In comparison to their results, several findings in our study suggest significant gender differences in the PTS/AT relationship: 1) the ATw in our sample of female subjects was found to be significantly lower than both the ATr and PTS, suggesting that the speed at the aerobic threshold in women depends on the modality of gait, and 2) the ATw was significantly correlated to both, PTS and ATr suggesting that the ATw could also be an important predictor of the PTS in young, untrained women. In summary, our results indicate that the gait transition speed corresponds to, and is highly related with the aerobic threshold for running and, to a lesser degree, with the aerobic threshold for walking in young women. Gender differences should be taken into consideration for proper interpretation of the coupling between the metabolic changes during locomotion, and leg muscle activation changes that supposedly determine, and are perceived at the PTS. REFERENCES 1. Šentija D, MarkoviC G (2009). The relationship between gait transition speed and the aerobic thresholds for walking and running. Int J Sports Med 30:795-801

gait transition; aerobic threshold; walking; running; women

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