Biomechanical P ... Slalom Water Skiing R1.pdf - Atrium - University ...

for patterns in the data that suggest outliers, unequal variance or other problems. Ifresidual analyses suggested a need for data transformation or data was presented as apercent, analyses were done on a logit or log scale. If the overall f test was significant atukey test was applied. (SAS Institue Inc. 2004. SAS OnlineDOC (R) 9.1.3. Cary, NC:SAS Institute Inc)3 ResultsThe mass of the four skis ranged from 3.81 to 4.63kg and the mass of the whole IMUsetup was 0.87 kg. The impact of additional weight was found to be negligible.Figure 4, Figure 5 and Figure 6 are examples of the typical streams of data that wereproduced from one ski run. All three of the figures were taken from the same run and thedata from when the collection program was started on the dock was excluded for clarity.Therefore, 0s in the figures is relative and not when the program was started. The majoractivities of interest can be easily identified from the figures. The first large peak in ropeload indicates the deep water start and the relatively large force that is required to pull askier out of the water (2000N at 20s). During this time the IMU is submerged underwater and therefore the RF signal is not being received. As the boat approaches its targetspeed and the skier begins to plane on top of the water, the rope load stabilizes to itsnominal value that is required to pull the subject across the water and the IMU signalbegins reception. The next smaller peak in rope load, positive roll peak and accelerationpeaks at 35s indicate the subject’s setup cut before entering the entrance gates of thecourse. The following series of rope load peaks, skier velocity peaks and oscillating roll39