Optimal load for a torque-velocity relationship test during cycling

Purpose Lower limbs’ neuromuscular force capabilities can only be determined during single sprints if the test provides a good fit of the data in the torque-velocity ( T – V ) and power-velocity ( P – V ) relationships. This study compared the goodness of fit of single sprints performed against traditional (7.5% of the body mass) vs. optimal load (calculated based on the force production capacity and ergometer specificities), and examined if reducing the load in fatigued state enhances T – V and P – V relationship goodness of fit. Methods Thirteen individuals performed sprints before (PRE) and after (POST) a fatiguing task against different loads: (1) TRAD: traditional, (2) OPT: optimal, and (3) LOW-OPT: optimal load reduced according to fatigue levels. Results At PRE, OPT sprints presented a higher R 2 of the T – V relationship (0.92 ± 0.06) and lower time to reach maximal power ( P max ) (48 ± 9%) when compared with TRAD sprints (0.89 ± 0.06 and 66 ± 22%, respectively, p < 0.01). At POST, the range of velocity spectrum was greater in the LOW-OPT (33 ± 4%) vs. TRAD (24 ± 3%) and OPT (26 ± 8%, p < 0.007). Similarly, the time to reach P max was lower in the LOW-OPT (46 ± 12%) vs. TRAD (76 ± 24%) and OPT (70 ± 24%, p < 0.006). Conclusion Sprints performed against an OPT load and reducing the OPT load after fatigue improve the fit of data in the T – V and P – V curves. Sprints load assignment should consider force production capacities rather than body mass.