Supervisors info:
Μπουντόλος Κωνσταντίνος, Καθηγητής, ΤΕΦΑΑ, ΕΚΠΑ
Εμμανουήλ Κωνσταντίνος, Αναπληρωτής Καθηγητής, ΤΕΦΑΑ, ΕΚΠΑ
Γελαδάς Νικόλαος, Επίκουρος Καθηγητής, ΤΕΦΑΑ, ΕΚΠΑ
Summary:
This study was designed to examine the Ground Reaction Forces (GRF) during a typical Aerobic Dance (AD) class, in a low (LI) and a high impact (HI) AD movement.
Twenty eight (28) aerobic dance instructors, (females=14, males=14) participated in this study. The mean values (SD) for age, height, mass and instructional experience were 26.7 (3.8) yrs, 168.0 (6.7) cm, 57.0 (7.1) kg, 6.4 (3.4) yrs and 27.0 (3.9) yrs, 182.4 (8.2) cm, 82.2 (9.8) kg, 5.9 (3.1) yrs, respectively. During a 35min AD exercise programme, eight 30s sampling periods took place (sampling rate 200Hz). The LI data were collected during the first four sampling periods (music cadence 144bpm) and the HI data during the subsequent four ones (music cadence 155 bpm). For the collection of data two forceplates were used (Kistler) which were mounted flush with a specifically constructed wooden floor, so as to record the GRF for the whole cycle of each movement (left foot leading). The data were analysed with the Bioware KistlerV.3 software for Windows 95. The statistical design was repeated measures three-way analysis of variance 2X(2XS)X(4XS).
In both LI and HI aerobic dance exercises, women developed significantly greater vertical forces and men significantly greater lateral forces. Between women and men, absolute peak time sequences of Fz and Fy were not significantly different, in both LI and HI exercises but relevant peak time sequences of Fz and Fy were significantly different only in LI exercise. The duration of left and right step as well as the duration of the cycle of movement and the duration of double support phase in LI and flight phase in HI were significantly shorter in women.
The significantly greater forces developed in shorter times in HI are in accordance with previous studies
Among the four impact trials the majority of the significant differences concern the differences between the first and second sampling trials and only in the case of LI exercise, possibly due to warm up adaptations.
These results show that the force pattern developed by AD instructors in the two exercises measured, was significantly differentiated by sex and type of impact but not by the performance time elapsed. It is suggested, with the use of appropriate techniques, further study for potential differences due to the performace time elapsed which were not detected in the present study as well as a more profound examination of the significant differences of GRF components between left and right foot.
