Measure of efficiency and knee isokinetic strength in bike messengers and non-cyclist athletes.

Background: Gross efficiency in cycling (GE) seems correlated with lower-body strength. This study investigated GE at four different pedaling rates and its relationship with an isokinetic strength test in bike messengers (BM) and experienced athletes non-bike messengers (NBM).

Methods: Eight BM and eight NBM completed a maximal incremental test to determine maximal aerobic power (MAP) and maximal oxygen consumption (V̇O2max). GE, V̇O2, heart rate (HR) and blood lactate concentration (BLC) were measured at different cadences (60, 70, 90 and 100 rpm) during an efficiency test at 50% of MAP and participants then performed an isokinetic test of the right knee.

Results: A difference in GE (except at 90 rpm), BLC and MAP/kg was found in favor of BM. The most efficient cadence was 60 rpm in both groups. Increased cadence resulted in decreased GE and increased HR and V̇O2 in both groups. BLC only increased in the NBM. We found no relationships between GE at different cadence, peak torque relative to bodyweight and muscle fatigability.

Conclusions: This study is the first investigating performance and efficiency among BM. At equivalent power output, BM show a better GE than NBM. Those results are in line with previously described analysis in cyclists and explained by better aerobic capacity and training status. Isokinetic knee maximal strength and fatigability were not linked with GE, and thus does not appear appropriate for evaluating GE in cycling.