Fig 1.
Typical body and pole positioning at pole plant during DP on the level (A) and on steep incline (B). The gravity component parallel to the surface, mgsin(α), increases with incline and induces greater speed losses whenever the poles are off the ground. If the same body positioning relative to the level ground were to be realized on an incline, external forces would likely lead to an unstable situation, e.g., the force of gravity (mg) would generate a moment at the base of support which would be hard to counteract by N or Fpole. Therefore, skiers alter body positioning on a slope compared to level skiing.
Fig 2.
Pole force and pole power against normalized time during uphill DP at shallow (INC5, 5%) and steep (INC12, 12%) inclines.
Lines are mean and shaded areas indicate 95% CI [N = 14].
Table 1.
Variables associated with uphill double-poling on roller-skis at shallow (INC5, 5%) and steep (INC12, 12%) inclines at increasing external power outputs.
Values are means ± 95% CI [N = 14].
Fig 3.
Joint angle and angular velocity against normalized cycle time during uphill DP at shallow (5%) and steep (12%) inclines.
Lines are means and 95% CI is indicated by shaded area [N = 14].
Fig 4.
Mechanical power against normalized cycle time at shallow (INC5, 5%) and steep (INC12, 12%) inclines in uphill DP.
Top, middle, and bottom panels represent low, moderate, and high external power, respectively. Lines represent mean with 95% CI indicated by shaded area [N = 14]. Pole power (Ppole), total muscle power output (Ptot), arm power (Parm), and trunk+legs power (PT+L). Also shown is the rate of change of mechanical energy associated with body movements perpendicular to the treadmill belt (). The vertical dashed lines represent end of poling phase.
Fig 5.
Power output and net moment about the elbow and shoulder joints in uphill DP at shallow (INC5, 5%) and steep (INC12, 12%) inclines at low, moderate, and high external power.
Lines represent mean with 95% CI indicated by shaded areas [N = 14].
Fig 6.
Average positive and negative power about the arms (arm) and legs and trunk (
T+L) for the poling (A-D) and swing (E-H) phases in uphill double-poling at increasing external power at shallow (INC5, 5%) and steep (INC12, 12%) inclines. Values are means and 95% CI [N = 14]. # indicates test for interaction; if sig. interaction, p-values are shown for simple main effect for each incline (5% and 12%) while if non-sig. interaction, p-values are shown for main effect of incline (Inc.) and WR (work rate); a,b, and c indicates sig. difference from low, mod, and high work rates at each incline, respectively (p<0.05), if sig. interaction or at pooled inclines if non-sig. interaction; * indicates sig. difference between inclines at the same work rate (p<0.05).
Fig 7.
Average absolute (A-B) and relative (C-D) arm power (arm) and leg and trunk (
T+L) power over the locomotion cycle in uphill DP at increasing external power at shallow (INC5, 5%) and steep (INC12, 12%) inclines. Values are mean and 95% CI [N = 14]. # indicates test for interaction; if sig. interaction, p-values are shown for simple main effect for each incline (5% and 12%) while if non-sig. interaction, p-values are shown for main effect of incline (Inc.) and WR (work rate); a,b, and c indicates sig. difference from low, mod, and high work rates at each incline, respectively (p<0.05); * indicates sig. difference between inclines at the same work rate (p<0.05).