Intersession reliability for H-reflex measurements arising from the soleus, peroneal, and tibialis anterior musculature.

The Hoffman reflex (H-reflex) has been widely used throughout neuroscience research, as it allows for the assessment of alpha motoneuron excitability arising from a specific motoneuron pool. Recently, a protocol has been developed allowing for the simultaneous examination of the soleus, peroneal, and tibialis anterior motoneuron pools elicited from a single peripheral stimulus. In order for this protocol to be useful, the reliability of the measures must be established. The purpose of the current study was to determine the intersession reliability of the soleus, peroneal, and tibialis anterior H-reflexes and their corresponding M-waves elicited from a single stimulus to the sciatic nerve. Ten healthy neurologically sound individuals (age: 23 +/- 7 yrs; height: 175 +/- 12 cm; mass: 76 +/- 22 kg) volunteered to participate in this investigation. To obtain the measurements, the sciatic nerve was stimulated just prior to its bifurcation into the tibial and common peroneal nerves in the popliteal fossa. A 1-ms square wave pulse was delivered in 0.2 V increments until the maximum M wave was seen in each muscle. The maximum H-reflex and M-waves were collected from each muscle and their ratios calculated. Intersession reliability over 2 consecutive days was estimated using intraclass correlation coefficients (ICC [2.1]). Intersession reliability for the soleus Max H, Max M, and H:M ratio were 0.9953, 0.9514, and 0.9747, respectively. The peroneal reliability measurements were as follows: 0.9979 (Max H), 0.9924 (Max M), and 0.9664 (H:M ratio). Intersession reliability was 0.8591, 0.9968, and 0.7810 for the tibialis anterior Max H. Max M. and H:M ratio, respectively. These results indicate that the H-reflex measured from the soleus, peroneal, and tibialis anterior musculature elicited with a single peripheral stimulus to the sciatic nerve is reliable between sessions. This protocol allows the clinician/researcher to reliably investigate the alpha motoneuron excitability of multiple motoneuron pools about the ankle at a single point in time.