PART 2: The Role of Quadriceps Function in Recovery and Performance

Why Quadriceps Function Matters

The quadriceps muscle group, composed of the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius, is essential for knee extension and dynamic stability. These muscles play an integral role in:

• Walking and running
• Rising from a seated position
• Climbing stairs
• Maintaining balance and avoiding falls

When the quadriceps are impaired, patients may compensate with altered gait mechanics, which can lead to secondary injuries or increased strain on surrounding joints and tissues.

Rehabilitation and Performance Implications

Functional Recovery

Rehabilitation targeting quadriceps strength is linked to improved performance in:

• Timed up and go (TUG) tests
• Single-leg hop tests
• Gait analysis metrics
• Return-to-sport benchmarks

Joint Protection and Longevity

Strengthening the quadriceps supports the joint by:

• Absorbing ground reaction forces
• Distributing load across the knee joint
• Enhancing proprioception and joint awareness
• Reducing the risk of re-injury and osteoarthritis progression

Neuromuscular Coordination

Effective rehab incorporates neuromuscular training that addresses:

• Joint position sense
• Movement pattern correction
• Symmetry in strength and control between limbs
• Core-to-limb kinetic chain efficiency

Neuromuscular Electrical Stimulation (NMES): A Game-Changer in Rehab

NMES involves the application of electrical impulses to elicit muscle contractions. It has gained popularity as an adjunct to traditional therapy, especially during early phases when voluntary activation is poor.

Key Benefits of NMES

Muscle Activation

• Enhances recruitment of motor units
• Supports contraction in the presence of neural inhibition
• Assists in early retraining of muscle firing patterns

Prevention of Atrophy

• Maintains muscle fiber size
• Preserves muscle mass
• Supports protein synthesis mechanisms

Pain Modulation

• Reduces perception of pain
• Facilitates greater participation in rehabilitation
• Improves overall exercise tolerance

Clinical Application of NMES

To be effective, NMES must be applied thoughtfully. Critical factors include:

Timing

• Initiated as early as tolerated post-surgery
• Delivered consistently (daily or several times weekly)
• Used in conjunction with volitional exercises

Parameters

• Current intensity sufficient to generate visible contractions
• Frequency typically ranging between 35–50 Hz
• On/off times to match patient tolerance and muscle recovery
• Electrode placement aligned with the quadriceps motor points