Ground reaction forces in high impact and low impact aerobic dance.

The purpose of this study was to compare ground reaction forces (vertical and lateral) produced during commonly used high and low impact aerobic dance maneuvers. Eight experienced aerobic dance instructors were the volunteer subjects. During the first session, three subjects were videotaped performing 10 high and 10 low impact maneuvers that they commonly used in their own class routines. Seven of the high and nine of the low impact maneuvers were then selected and used in sessions 2 and 3. During the second session, all subjects became proficient in performing the chosen maneuvers to music while striking an AMTI force platform with the right foot. During the third session, ground reaction force data generated during footstrike were recorded for each movement. Of the maneuvers examined, 5 high and four low impact maneuvers were used in the data analysis. It was found that maximum vertical active peak and vertical impact peak forces were lower for the low impact maneuvers. Maximum lateral active peak and lateral impact peak forces were similar and highly variable in magnitude for the 2 types of dance. The lower vertical loads produced in low impact dancing may make this type of dance better for minimizing lower extremity overuse injuries in aerobic dance. However, there does not seem to be any advantage in emphasizing the use of low impact dance for minimizing lower extremity injuries that evolve from lateral shear forces.