An investigation into the architecture of the vastus medialis oblique muscle in athletic and sedentary individuals: An in vivo ultrasound study

Abstract

There is thought to be a relationship between the vastus medialis oblique muscle (VMO) and patellofemoral pain syndrome (PFPS), a condition that has a high prevalence in young athletic individuals. Following a suggestion that there may be a link between the architecture of the VMO and an individual's activity level, the aim of this study was to determine any differences in two measurable parameters of the VMO between two populations with widely differing activity levels. The parameters measured were VMO fiber angle and insertion ratio, which is the proportion of the medial patellar border with VMO fibers inserting onto it (%). Eighty-two knees from 26 athletic volunteers and 15 sedentary volunteers (aged 20-28 years) were assessed using ultrasound. Activity level was defined using the Tegner scoring system. The mean VMO angle (°) for the athletic group was significantly higher than for the sedentary group at 67.8° and 53.6°, respectively. There was no significant difference in insertion ratio between the athletic group, 43.0%, and the sedentary group, 39.5%. This study found that greater VMO fiber angles were seen in individuals with higher activity levels, exerting a stronger medial stabilizing force on the patella. This has important implications for the treatment of PFPS, particularly in athletic patients, which frequently focus on VMO strengthening exercises.

Open-chain and closed-chain exercise regimes: an ultrasound investigation into the effects of exercise on the architecture of the vastus medialis oblique

“…A study by Benjafield et al, [29] found an average insertion ratio of 43.0% in athletic individuals, compared to 39.5% in sedentary individuals (the overall initial ratio in our study was 36.83%, which supports the low Tegner scores reported by the participants). The increase in insertion length, and hence increased ratio, following the exercise programme, enables a greater medial pull on the patella by the VMO, facilitating doi: 10.7243/2055-2386-4-3 correction of the lateral tilt and shift often seen in PFPS.…”

“…The ultrasound technique used in this study followed the method that has been validated and described in several previous studies [18,[25][26][27][28][29]. Participants were positioned supine on the examination couch; a pillow was placed under the ankles to immobilise the lower limbs.…”

“…The application of ultrasound in investigations into skeletal muscle architecture has been demonstrated in multiple studies (e.g., [23,24]). The method used here has been validated [25], and has been used in previous investigations into the VMO [18,[26][27][28][29].…”

The effect of exercise on vastus medialis oblique muscle architecture: An ultrasound investigation

“…However data from asymptomatic in vivo investigations are limited. A study by Benjafield et al () on subject groups with differing activity levels found an average VMO fiber angle of 67.8° for athletic groups (Tegner score > 7), and 53.6° for sedentary groups (Tegner score < 3). The average VMO fiber angle of 62.24° reported here before exercise is within the expected range as the study was limited to subjects with a Tegner score of 5 or less.…”

“…Three measurements were recorded in each procedure: patella length, insertion length and VMO fiber angle. The methodology used here follows previous studies in which the ultrasound technique has been shown to be statistically robust and accurate (Lin et al, ; Jan et al, , Engelina et al, ; Engelina et al, , Benjafield et al, ).…”