This study aimed (i) to compare electrical and magnetic stimulations for quadriceps muscle function assessment and (ii) to ascertain whether the ratios of the second twitch elicited by supramaximal electrical and magnetic femoral nerve stimulation at 10 and 100Hz (T2_10:100) and the total twitch force elicited by the same types of stimulations (Fpaired_10:100) are equivalent to the standard low-to-high frequency force ratio associated to submaximal electrical tetanic stimulations (Ftet_10:100). Quadriceps force and vastus lateralis EMG were recorded at rest (n=21 subjects), immediately after and 30min after a 30-min downhill run (n=10) when i) supramaximal electrical nerve stimulation (ENS), ii) magnetic nerve stimulation (MNS) and iii) submaximal electrical muscle stimulation (EMS) were delivered in random order at 1Hz (single stimulation), 10Hz and 100Hz (paired stimulations). Ten and 100Hz 500-ms tetani were also evoked with EMS to determine Ftet_10:100. Before exercise, contractile properties with single and paired stimulations were similar for ENS and MNS (all intraclass correlation coefficients k>0.90), but smaller for EMS (p<0.001). M-wave characteristics were also similar for ENS and MNS (all k>0.90). After exercise, changes in all parameters did not differ between methods. With fatigue, the changes in Ftet_10:100 were inconsistently correlated with the changes in T2_10:100 (r²=0.24-0.73, p=0.002-0.15) but was better correlated with the changes in Fpaired_10:100 (immediately after exercise: r²=0.80-0.83, p<0.001; 30min after exercise: r²=0.46-0.82, p=0.001-0.03). We conclude that ENS and MNS provide similar quadriceps muscle function assessment, while Fpaired_10:100 is a better index than T2_10:100 of low-to-high frequency fatigue of the quadriceps in vivo.