Strength Training Provides Several Noted Benefits to Women With Myotonic Dystrophy Type 1

Elise Duchesne, PhD

A study published in Neuromuscular Disorders showed that 12-week supervised strength training program resulted in increased maximal hip and knee extension muscle strength, lowered apathy and anxiety, and induced muscle hypertrophy in women with myotonic dystrophy type 1 (DM1). In addition to highlighting the potential benefits of a physical training program, the study provided additional findings to initiate the development of evidence-based guidelines for exercise prescriptions for patients with DM1.¹

The 12-week training program, which was previously tested in a cohort of men with DM1, involved twice-weekly supervised sessions at the gym of the University of Quebec at Chicoutimi, including 5 lower limb exercises (leg extension, leg press, hip abduction, squat, and plantar flexion). Each training session started with a 5-minute warm-up on a bike at low to moderate intensity, followed by 3 sets of 6 to 8 repetitions of each lower limb exercise with a 2-minute rest between sets. During subsequent sessions, if the participant could complete more than 8 repetitions, weight was increased by 10% till the participant did not exceed 8 repetitions.

Led by senior author Elise Duchesne, a professor at the University of Quebec, 11 of the 12 women recruited completed the training program, with 1 participant excluded due to medical reasons, despite completing 6 weeks of the training program. The cohort had a mean age of 37.3 (±10.5) years and an average of 490 (±272) CTGn repeats. For the follow-up evaluations, 10 participants attended the 3-month follow-up and 8 participated in the 6-month follow-up.

Assessment schedule for the training program was as follows: T0 and T2: all muscle groups; T1: knee extensors only; T3 and T4: knee and hip extensors only. All told, the training induced a significant increase in MIMS of the knee extensors (71 [±31] Nm at T0 vs 80 [±34] Nm at T2; P = .006) with a significant gain in the first half of the training program (71 [±31] Nm at T0 vs 80 [±31] Nm at T1; P = .013).

Patients did not demonstrate significant improvements in their functional mobility and comfortable walking speed following the completion of the training program, but did show a tendency of improvement for the 30 s STS (12.86 [±2.93] repetitions at T0 vs 13.91 [±1.92] repetitions at T2; P = .058). In addition, there was a significant improvement in walking speed at the maximal pace between the baseline and 6-week assessments (1.58 [±0.42] m/s at T0 vs. 1.68 [±0.45] m/s at T1; P < 0.010), but no significant effect was measured at the end of the training program (T0 vs. T2).

READ MORE: Pitolisant Reduces Excessive Daytime Sleepiness and Fatigue in Myotonic Dystrophy Type 1

Although there were no observed significant changes in fatigue and somnolence with the training program, participants showed significant decreases on AES-C scale, a measure of apathy, over the 12-week period (34.58 [±8.34] at T0 vs 31.18 [±7.65]; P <.001). Interestingly, there was no significant increase in apathy scores in the late stage of the study (T2 vs 32.38 [±7.52] at T4; P = .414). Findings also revealed an improvement in depression symptomatology, indicated by a significant decrease in the subscale of depression in HADS score after 12 weeks (3.75 [±2.70] at T0 vs 2.64 [±1.36] at T2; P = .021).

Over the 12-week period, participants saw significant increases (64.58 [±14.84] at T0 vs 70.91 [±11.26] at T2; P = .003) in Lower Extremity Functional Scale, a patient-reported outcome, that lasted up to T4. Although participants still experienced pain throughout the study, pain score interference significantly improved, leading to less effect on daily activities (P = .015). Notably, this significant improvement was maintained up to 6 months after the end of the training program.

In terms of other patient-reported outcomes and self-reported changes, several patients demonstrated increased energy level (n = 4), better mood (n = 3), increased lower limb strength and endurance (n = 8), improvement in physical capabilities related to mobility (n = 7), improvement in balance (n = 4), and greater self-esteem (n = 5). In contrast, fatigue induced by the training was also reported (n = 3). To help adherence, patients noted supervision of training sessions, flexible schedules, being paired with other persons with the same disease, and affordability as main facilitators. Inclusion of training schedules in daily schedule was seen as a principal barrier; however, participants felt as though they would recommend the training to other patients with DM1.

REFERENCE
1. Girard-Cote L, Gallais B, Gagnon C, et al. Resistance training in women with myotonic dystrophy type 1: a multisystemic therapeutic avenue. Neuromusc Disord. 2024;40:38-51. doi:10.1016/j.nmd.2024.05.009