Manual therapy directed at the knee or lumbopelvic region does not influence quadriceps spinal reflex excitability

Abstract

Manual therapies, directed to the knee and lumbopelvic region, have demonstrated the ability to improve neuromuscular quadriceps function in individuals with knee pathology. It remains unknown if manual therapies may alter impaired spinal reflex excitability, thus identifying a potential mechanism in which manual therapy may improve neuromuscular function following knee injury.

Aim: To determine the effect of local and distant mobilisation/manipulation interventions on quadriceps spinal reflex excitability.

Methods: Seventy-five individuals with a history of knee joint injury and current quadriceps inhibition volunteered for this study. Participants were randomised to one of five intervention groups: lumbopelvic manipulation (grade V), lumbopelvic manipulation positioning (no thrust), grade IV patellar mobilisation, grade I patellar mobilisation, and control (no treatment). Changes in spinal reflex excitability were quantified by assessing the Hoffmann reflex (H-reflex), presynaptic, and postsynaptic excitability. A hierarchical linear-mixed model for repeated measures was performed to compare changes in outcome variables between groups over time (pre, post 0, 30, 60, 90 min).

Results: There were no significant differences in H-reflex, presynaptic, or postsynaptic excitability between groups across time.

Conclusions: Manual therapies directed to the knee or lumbopelvic region did not acutely change quadriceps spinal reflex excitability. Although manual therapies may improve impairments and functional outcomes the underlying mechanism does not appear to be related to changes in spinal reflex excitability.

Keywords: H-reflex; Knee pain; Manipulation; Mobilization.

Figure 1

CONSORT Flow Chart.

Figure 2

Lumbopelvic joint manipulation. Participants were supine on the testing bed, while the physical therapist stood on the opposite side to be manipulated. The participant was passively side-bent away and rotated towards the physical therapist. After positioning, the physical therapist delivered a low amplitude, high velocity thrust directed through the anterior superior iliac spine (ASIS) in a posterior/inferior direction.

Figure 3

Patella mobilisation (Grade IV and I). The patient was in a supine position with the knee in full extension. The physical therapist placed both thumbs on the lateral aspect of the patella while the fingers of both hands rested across the tibia and femur pointing in a medial direction. The grade IV mobilisation was performed by first engaging the end limit of medial patella excursion. Next, small amplitude oscillations in a medial direction were performed at the end limit of the available motion and stressed into tissue resistance. A grade I mobilisation was performed using small amplitude rhythmic oscillations performed at the beginning of the range of movement and did not engage the end range of motion.