Resistance training alone and combined resistance and aerobic training both lead to significant improvements in muscle thickness and pennation angle in patients with hemophilia, according to a new study published in Haemophilia.

The study was a randomized, controlled trial that enrolled 42 individuals with moderate hemophilia A who were aged 35 to 55 years and had a body mass index of 25 to 30 kg/m2.

“Given the synergistic pathophysiological effect of obesity and hemophilia, increasing muscle strength in [people with hemophilia] helps maintain their normal joint function and improve their quality of life,” the authors said.

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“Both [resistance training] and [combined resistance and aerobic training] were effective in enhancing [muscle thickness] and [pennation angle] in overweight persons with moderate hemophilia A.”

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The participants were randomly assigned to the resistance training group, the combined resistance and aerobic training group, or the control group. The resistance training and combined resistance and aerobic training groups completed eighteen 40- to 45-minute sessions, 3 times per week, for 6 weeks.

The research team employed musculoskeletal ultrasonography to assess muscle thickness and pennation angle 72 hours after the final exercise session, given that ultrasonography is safe, noninvasive, and reliable for these types of measurements. The exercise protocol was found to be safe and effective, and no bleeding episodes occurred in any of the study participants.

Deficits in muscle strength are common in patients with hemophilia, and overweight and obesity can lead to a greater risk of joint disorders and bleeding in these patients. The results from this study can help clinicians prescribe a therapeutic exercise regimen for patients with moderate hemophilia A.

The authors recommend a pilot study to assess the effectiveness of this exercise protocol and musculoskeletal ultrasonography in patients with severe hemophilia who have joint damage and chronic pain.


Parhampour B, Alizadeh V, Torkaman G. Muscle thickness and pennation angle in overweight persons with moderate haemophilia A after resistance and combined training: a randomized controlled trial. Haemophilia. Published online March 8, 2022. doi:10.1111/hae.14539