What exercises strengthen the Vastus Medialis Oblique (VMO) muscle?

VMO Strengthening Exercises

Progressive quadriceps strengthening through both open and closed kinetic chain exercises effectively strengthens the vastus medialis oblique (VMO), with the most recent evidence from 2024 supporting knee-targeted exercise therapy as the primary approach for conditions involving VMO weakness. 1

Primary Exercise Approach

Knee-targeted exercise therapy should form the foundation of VMO strengthening, utilizing progressive loading of the quadriceps through both open and closed chain movements. 1 The British Journal of Sports Medicine guidelines from 2024 demonstrate high certainty evidence (SMD 1.16) for knee-targeted exercise therapy in reducing pain and improving function. 1

Specific Exercise Recommendations

Closed kinetic chain exercises:

• Leg press - Can be safely initiated as early as 3 weeks post-injury in rehabilitation settings, improving subjective knee function and functional outcomes 1
• Squats - Full range squats activate VMO effectively 2
• Step-down exercises - Demonstrated to reduce pain by 94% in patellofemoral pain patients, though VMO/VL ratio remains unchanged 3

Open kinetic chain exercises:

• Terminal knee extension (last 30 degrees) - Produces the highest VMO/VL activation ratio of 1.2 when performed with hip medially rotated 3
• Seated knee extension from 90° to full extension - Can be safely introduced at 4 weeks post-injury, progressing from 90° to 40°, then 90° to 20°, then full range 1
• Straight leg raises with isometric quadriceps contractions - Safe during the first 2 postoperative weeks, conferring advantages for faster recovery without compromising stability 1

Exercise Prescription Parameters

Frequency and volume:

• Minimum 2 days per week, progressing to 3 days per week 1
• Single set of 10-15 repetitions at moderate intensity (40-60% 1-RM) for general populations 1
• 8-12 repetitions for younger adults (under 50-60 years) 1
• Perform exercises through full range of motion at moderate to slow controlled speed 1

Progressive loading strategy:

• Start with isometric exercises (static quadriceps contractions) in the initial phase 1
• Progress to dynamic exercises with eccentric and concentric components (leg press) by week 3 1
• Advance to isokinetic strengthening by week 3-9 depending on graft type and surgical status 1

Hip and Knee Combined Approach

Hip-and-knee-targeted exercise therapy demonstrates secondary efficacy superior to knee exercises alone for patellofemoral pain conditions. 1 This combined approach addresses the entire lower extremity kinetic chain, which experts and patients advocate for comprehensive quadriceps strengthening. 1

Hip strengthening components:

• Hip abduction exercises
• Hip external rotation exercises
• Hip extension exercises
• These should be performed 2-3 days per week alongside knee-targeted exercises 1

Adjunctive Techniques

VMO biofeedback combined with exercise therapy shows efficacy when part of a multimodal program including hip-and-knee exercises, soft tissue stretching, and McConnell-style patellar taping. 1 However, this combination approach is more complex than knee-targeted exercise alone.

Hip rotation positioning during exercises:

• Terminal knee extension with hip medially rotated produces VMO/VL ratio of 1.2 3
• Hip laterally rotated produces ratio of 1.0 3
• Isometric knee extension in neutral or external hip rotation challenges both VMO and VL equally 2

Critical Evidence Considerations

The concept of selective VMO isolation remains controversial. While one 2024 study claims selective VMO strengthening is achievable through specific protocols 4, multiple earlier studies from 1995-1999 consistently found that VMO cannot be significantly isolated from the other quadriceps components during standard exercises 5, 2, 3. The 1999 study specifically concluded that "the vastus medialis oblique muscle cannot be significantly isolated during these exercises." 2

Practical implication: Rather than attempting selective VMO isolation, focus on general quadriceps strengthening with emphasis on terminal knee extension and hip positioning to optimize VMO/VL ratios. 3

Common Pitfalls to Avoid

• Avoiding open kinetic chain exercises entirely - These can be safely introduced at 4 weeks post-injury without compromising stability when progressed appropriately 1
• Delaying weight-bearing - Early weight-bearing (immediate) reduces patellofemoral pain from 35% to 8% without compromising laxity 1
• Excessive focus on VMO isolation - The evidence suggests this is not achievable with standard exercises; instead, strengthen the entire quadriceps complex 5, 2, 3
• Inadequate exercise frequency - Minimum 2 days per week required, with 3 days optimal 1
• Breathholding during exercises - Exhale during contraction phase, inhale during relaxation to avoid Valsalva maneuver 1

Exercise Progression Timeline

Weeks 1-2: Isometric quadriceps contractions and straight leg raises 1

Weeks 3-4: Add leg press and progress to dynamic exercises with eccentric/concentric components 1

Weeks 4-6: Introduce open kinetic chain exercises (seated knee extension) starting from 90° to 45°, progressing to full range 1

Weeks 6-12: Progress to isokinetic strengthening and sport-specific activities 1