Learning with a lever-propelled wheelchair: the effect of three weeks of practice on efficiency and technique

Lever-propelled wheelchairs are alternatives to hand-rim propelled wheelchairs that could potentially be used to prevent overuse injuries. The NuDrive is a detachable lever-propulsion system that enables an upright posture, potentially beneficial in preventing back problems. It also provides a continuous grip, very suitable for users with a limited hand function. These advantages make the NuDrive an interesting option for rehabilitation. However, using the NuDrive adequately is suggested to require a process of adaptation, i.e. motor learning. Therefore, we investigated the effects of three weeks of practice on technique and efficiency. Methods Inexperienced able-bodied male participants were randomly divided over an experimental (EXP, n=8) and a control group (CON, n=8). Pre- and posttest for both groups were three weeks apart and consisted of three consecutive 4 min bouts of sub-maximal exercise, with 2 min rest in between. EXP performed seven practice trials spread over the three weeks, to become more and more familiarized to the lever-propulsion. These trials consisted of two consecutive 4 min bouts of sub-maximal exercise, with 2 min rest in between. All tests and trials were performed on a motorized treadmill (0.30 W/kg, 1,11 m/s). Changes in technique were measured using: stroke frequency, push time(PT), cycle time(CT), hand-speed and lever range of motion (lever ROM). Learning effects were quantified using gross mechanical efficiency (GME). Statistics: ANOVA p>0.05 Results PT(EXP:CON;+0.11(�0.10)s:+0.02(�0.02)s) and lever ROM (+12.8(�14.1)deg: +1.1(�4.3)deg) increased, where maximal hand-speed during the push phase (EXP:CON;-0.17(�0.14)m/s: 0.0(�0.09)m/s) decreased more in EXP compared to CON, indicating that EXP participants shifted to a movement pattern with a longer stroke range and slower movement of the hands: a longer-slower movement pattern. Some indication of an increased GME was found, however, nothing conclusive, potentially due to a low participant number in the GME analysis (EXP, n=5; CON, n=7). Conclusion EXP participants adopted a longer-slower movement pattern after three weeks of practice. Maximal hand-speed only decreased during the push phase. This indicates that participants might be more inclined to change their technique during the active push phase compared to the more passive pull phase. Inexperienced new users of the NuDrive might benefit from a focus on a longer-slower movement pattern early in their learning trajectory, although more research is needed to establish the effect of practice trials on GME.