Assessment of muscle coordination during cycling can provide insight into motor control strategies and movement efficiency. This study evaluated muscle synergy patterns as indicators of neuromuscular Show more
Assessment of muscle coordination during cycling can provide insight into motor control strategies and movement efficiency. This study evaluated muscle synergy patterns as indicators of neuromuscular coordination in the lower limbs across three power levels of cycling (LPL = Lowest Power Level, MPL = Middle Power Level, HPL = Highest Power Level). Twenty recreational cyclists performed a graded cycling test on a stationary bicycle ergometer. Electromyography (EMG) was recorded bilaterally from seven lower-limb muscles and muscle synergies were extracted using non-negative matrix factorization. The Synergy Index (SI) and Synergy Coordination Index (SCI) were calculated to assess muscle coordination patterns. Four muscle synergies were identified consistently across power levels, with changes in synergy composition and activation timing correlated with increasing muscular demands. At the dominant hip, SI remained consistent across power levels (0.50 ± 0.11 at LPL, 0.56 ± 0.15 at MPL, 0.54 ± 0.15 at HPL). At the dominant knee, SI decreased with increasing power (0.47 ± 0.07 at LPL to 0.34 ± 0.05 at HPL; p < 0.01, η These findings provide insight into how the central nervous system modulates its response to increasing mechanical demands. Combining synergy indices offers a promising approach to assess motor control, inform rehabilitation, and optimize performance in cycling tasks. Show less
HCM is the most common inherited cardiomyopathy. Historically, there has been poor correlation between genotype and phenotype. However, CMR has the potential to more accurately assess disease phenotyp Show more
HCM is the most common inherited cardiomyopathy. Historically, there has been poor correlation between genotype and phenotype. However, CMR has the potential to more accurately assess disease phenotype. We characterized phenotype with CMR in a cohort of patients with confirmed HCM and high prevalence of genetic testing. Patients with a diagnosis of HCM, who had undergone contrast-enhanced CMR were identified. Left ventricular mass index (LVMI) and volumes were measured from steady-state free precession sequences. Late gadolinium enhancement (LGE) was quantified using the full width, half maximum method. All patients were prospectively followed for the development of septal reduction therapy, arrhythmia or death. We included 273 patients, mean age 51.2 ± 15.5, 62.9% male. Of those patients 202 (74.0%) underwent genetic testing with 90 pathogenic, likely pathogenic, or rare variants and 13 variants of uncertain significance identified. Median follow-up was 1138 days. Mean LVMI was 82.7 ± 30.6 and 145 patients had late gadolinium enhancement (LGE). Patients with beta-myosin heavy chain (MYH7) mutations had higher LV ejection fraction (68.8 vs 59.1, p<0.001) than those with cardiac myosin binding protein C (MYBPC3) mutations. Patients with MYBPC3 mutations were more likely to have LVEF < 55% (29.7% vs 4.9%, p = 0.005) or receive a defibrillator than those with MYH7 mutations (54.1% vs 26.8%, p = 0.020). We found that patients with MYBPC3 mutations were more likely to have impaired ventricular function and may be more prone to arrhythmic events. Larger studies using CMR phenotyping may be capable of identifying additional characteristics associated with less frequent genetic causes of HCM. Show less