Longitudinal changes in Achilles tendon and triceps surae muscle architecture during a 156-km mountain ultramarathon.

This study aimed to assess the longitudinal changes in triceps surae muscle-tendon architecture during a mountain ultramarathon. Experienced trail runners [n = 55, 78% men, age: 45.2 (13.5) yr] participated in a 156-km trail run (6,000 m climbing) consisting of six 26-km laps. The resting architectural properties of triceps surae muscle-tendon were measured using ultrasound imaging for Achilles tendon cross-sectional area (AT CSA), medial gastrocnemius muscle pennation angle, thickness, length, and fiber length. Measurements were performed the day before the race (baseline), at 52 km (T1), at 104 km (T2), at 156 km (T3), and 12 h after the race (H12). Among finishers (n = 41), there was a significant biphasic change in AT CSA during the race (P = 0.001). First, a significant decrease in AT CSA occurred between baseline and T1 (P = 0.006), with a greater decrease for participants averaging speed >8 km/h (P = 0.014). Second, there was a significant increase in AT CSA especially between T2 and T3 (P = 0.006) that was correlated with a decrease in average speed (P = 0.001) and alteration of spaciotemporal running parameters (P < 0.05). Changes in muscle-tendon architecture were not significantly different between finishers (n = 41) and nonfinishers (n = 14). In 47 participants (85.5%) who completed the follow-up, AT CSA at H12 was greater compared with baseline (P = 0.010). The main finding is the significant and biphasic modification of the AT CSA during a 156-km mountain ultramarathon with an initial decrease corresponding to mechanical stress followed by a secondary increase suggesting adaptive mechanotransduction persisting after 12 h.NEW & NOTEWORTHY Achilles tendon cross-sectional area (AT CSA) demonstrated significant adaptive modifications during a 156 km mountain ultramarathon in trained athletes. Initially, a decrease in AT CSA, especially at higher running speeds, is consecutive to the biomechanical stress on the plantar flexor muscle-tendon unit (MTU). Subsequently, there is a significant increase in AT CSA persisting up to 12 h after the race, which likely corresponds to an adaptive process to limit the compressive and tensile load on the tendon.

Effects of a 20-Week High-Intensity Strength Training Program on Muscle Strength Gain and Cardiac Adaptation in Untrained Men: Preliminary Results of a Prospective Longitudinal Study.

BACKGROUND: As strength sports gain popularity, there is a growing need to explore the impact of sustained strength training on cardiac biventricular structure and function, an area that has received less attention compared to the well-established physiological cardiac adaptation to endurance training. OBJECTIVE: This study aims to implement a 20-week high-intensity strength training program to enhance maximal muscle strength and evaluate its impact on cardiac biventricular adaptation in healthy, untrained men. METHODS: A total of 27 healthy and untrained young men (mean age 22.8, SD 3.2 years) participated in a strength training program designed to increase muscle strength. The training program involved concentric, eccentric, and isometric exercise phases, conducted over a consecutive 20-week time frame with a frequency of 3 weekly training sessions. Participants were evaluated before and after 12 and 20 weeks of training through body composition analysis (bioelectrical impedance), a 12-lead resting electrocardiogram, 3D transthoracic echocardiography, cardiopulmonary exercise testing, and muscle isokinetic dynamometry. The progression of strength training loads was guided by 1-repetition maximum (RM) testing during the training program. RESULTS: Of the initial cohort, 22 participants completed the study protocol. No injuries were reported. The BMI (mean 69.8, SD 10.8 kg/m² vs mean 72, SD 11 kg/m²; P=.72) and the fat mass (mean 15.3%, SD 7.5% vs mean 16.5%, SD 7%; P=.87) remained unchanged after training. The strength training program led to significant gains in 1-RM exercise testing as early as 4 weeks into training for leg extension (mean 69.6, SD 17.7 kg vs mean 96.5, SD 31 kg; P<.001), leg curl (mean 43.2, SD 9.7 kg vs mean 52.8, SD 13.4 kg; P<.001), inclined press (mean 174.1, SD 41.1 kg vs mean 229.2, SD 50.4 kg; P<.001), butterfly (mean 26.3, SD 6.2 kg vs mean 32.5, SD 6.6 kg; P<.001), and curl biceps on desk (mean 22.9, SD 5.2 kg vs mean 29.6, SD 5.2 kg; P<.001). After 20 weeks, the 1-RM leg curl, bench press, pullover, butterfly, leg extension, curl biceps on desk, and inclined press showed significant mean percentage gains of +40%, +41.1%, +50.3%, +63.5%, +80.1%, +105%, and +106%, respectively (P<.001). Additionally, the isokinetic evaluation confirmed increases in maximal strength for the biceps (+9.2 Nm), triceps (+11.6 Nm), quadriceps (+46.8 Nm), and hamstrings (+25.3 Nm). In this paper, only the training and muscular aspects are presented; the cardiac analysis will be addressed separately. CONCLUSIONS: This study demonstrated that a short-term high-intensity strength training program was successful in achieving significant gains in muscle strength among previously untrained young men. We intend to use this protocol to gain a better understanding of the impact of high-intensity strength training on cardiac physiological remodeling, thereby providing new insights into the cardiac global response in strength athletes. TRIAL REGISTRATION: ClinicalTrials.gov NCT04187170; https://clinicaltrials.gov/study/NCT04187170.

Personality Traits Associated with the Risk of Exercise Dependence in Ultraendurance Athletes: A Cross-Sectional Study.

Exercise dependence (ED) is common in endurance athletes and can lead to physical and psychological distress with various health effects. We designed a prospective cross-sectional study to investigate the personality traits associated with ED among ultraendurance athletes. A total of 507 participants (41.6 (9.8) years, men: 73.7%) completed (1) a screening questionnaire about sociodemographic data, sporting habits, and healthcare data, (2) the Exercise Dependence Scale-Revised (EDS-R, 21 items scored from 1 (never) to 6 (always), 7 subscales), (3) the Big Five Inventory (BFI), and (4) 2 items of the SCOFF (Sick-Control-One Stone-Fat-Food) questionnaire regarding possible eating disorders. Based on the EDS-R scores, 37 (7.3%) participants were at risk for ED (scores ≥ 5/6 on ≥3 subscales), 366 (72.2%) were nondependent but symptomatic (scores ≥ 3/6 on ≥3 subscales), and 104 (20.5%) were asymptomatic. Participants with ED had a greater training volume and a higher prevalence of possible eating disorders. A higher level of neuroticism was associated with increased EDS-R scores (r = 0.294; p < 0.001), with significantly higher scores in the ED group (F = 14.50, p < 0.001). The association between neuroticism and ED was not moderated by the presence of eating disorders. These findings will help to screen ultraendurance athletes at risk for ED and optimize their care.