How can I modify my exercise routine to avoid overexerting my quadriceps, which seem to be doing all the work during squats, given my condition of Duchenne muscular dystrophy (DMD)?

Exercise Modification for Duchenne Muscular Dystrophy with Quadriceps-Dominant Squatting

You should avoid traditional squats entirely and instead focus on low-resistance, self-paced activities that do not isolate or overload specific muscle groups, as forced resistance exercise may cause additional muscle damage in DMD. 1

Why Traditional Squats Are Problematic in DMD

Your observation about quadriceps dominance during squats reflects the progressive, asymmetric muscle weakness pattern in DMD where certain muscle groups fail earlier than others, forcing compensatory overuse of remaining functional muscles. 2, 3

• The hip extensors (gluteal muscles) are among the muscles that weaken early in DMD, which explains why your hips feel "dormant" during squats—they literally cannot activate properly due to dystrophic muscle damage. 2
• Forcing quadriceps to compensate for weak hip muscles accelerates damage to the quadriceps themselves, as dystrophic muscle is highly vulnerable to contraction-induced injury. 1
• Resistance training protocols designed for healthy individuals or cardiac patients are not appropriate for DMD, as the underlying pathophysiology involves progressive muscle fiber destruction that worsens with eccentric loading. 1

What Exercise IS Safe and Beneficial in DMD

Voluntary, self-paced exercise like walking or voluntary wheel running (the human equivalent being cycling or swimming at your own pace) has been shown to improve muscle function WITHOUT worsening the dystrophy. 4, 5

Recommended Exercise Approach:

• Engage in low-intensity, volitional activities such as swimming, stationary cycling, or walking where you control the pace and can stop when fatigued. 4
• Avoid eccentric contractions (the lowering phase of squats) which cause the most damage to dystrophic muscle. 4, 5
• Focus on activities that promote a slow, oxidative muscle phenotype rather than high-force contractions—this means sustained, gentle movement rather than strength training. 4
• Exercise should feel comfortable and self-limited; if a muscle group feels like it's doing "all the work," that activity is inappropriate for DMD. 4

Evidence Supporting This Approach:

Research in severe DMD mouse models (D2.mdx) demonstrates that voluntary wheel running at self-selected intensities improved muscle mass, force generation, and mitochondrial function without exacerbating pathology. 4 Importantly, even low-volume voluntary exercise (0.46 km/day) provided benefits, while high-volume runners (1.84 km/day) showed dose-dependent improvements in muscle quality and reduced fibrosis. 4

In contrast, forced submaximal resistance exercise in DMD patients showed only limited benefit and carries theoretical risk of accelerating muscle damage. 6

Physical Therapy Recommendations for DMD

Work with a physical therapist experienced in neuromuscular disease to develop a stretching and gentle range-of-motion program, NOT a strengthening program. 2, 3, 7

• The primary goal is preventing contractures and maintaining flexibility, particularly in hip flexors, knee flexors, ankle plantar flexors, and iliotibial bands. 2
• Stretching should be performed daily, focusing on heel cord stretching and hip/knee range of motion. 7
• Strengthening exercises are NOT the priority in DMD management—maintaining function through flexibility and preventing compensatory patterns is more important. 2, 7

Monitoring Recommendations:

• Assess muscle strength and function every 6 months using standardized measures like timed 10-meter walk, 4-stair climb, and rise from chair tests. 2
• If you notice increasing difficulty with specific movements or new compensatory patterns (like your quadriceps-dominant squatting), this signals progression requiring adjustment of your activity program. 2

Critical Pitfall to Avoid

Do not attempt to "strengthen" weak muscle groups through resistance training in DMD. The muscle weakness is due to progressive destruction of muscle fibers that cannot be reversed through exercise, and attempting to do so may accelerate damage. 1, 4 The defective nitric oxide release mechanism in DMD muscle means that exercise-induced muscle damage may be greater than in healthy individuals. 1

What About Your Hip Muscles Specifically?

Your "dormant" hips reflect genuine muscle weakness from dystrophic pathology, not deconditioning that can be fixed with exercise. 2, 3

• Consider ankle-foot orthoses if you develop ankle weakness, as these can help prolong functional mobility without forcing compensatory patterns. 2
• Discuss with your neuromuscular specialist whether you need assistive devices rather than trying to force weakened muscle groups to work harder. 2, 7
• Focus on maintaining what function you have through gentle, self-paced activity rather than trying to build strength in failing muscle groups. 4, 5