ECSS Paris 2023: OP-MH09
INTRODUCTION: Youth participation in sports is beneficial for physical and mental health, however early specialization and repetitive movements, can cause overuse injuries and imbalances in the body. One of such groups are overhead athletes where most strain is on the upper extremities (ex: volleyball, basketball, handball and others)[1]. The restricted range of motion and weakness in rotator cuff muscles are the modifiable injury risk factors, that can be caused by muscle imbalances, excessive training loads and poor biomechanics [1,2]. Some studies of overhead athletes show higher shoulder injury rates specifically in 15-18 years old comparing to male athletes [2]. Aim of this research was to present comparison of shoulder range of motion and isometric strength in overhead youth female athletes. METHODS: Fifty seven youth female overhead athletes participated in pre- season testing representing overhead athletes group basketball (n=9), volleyball (n=19), handball (n=16), tennis (n=4), swimming (n=4), rock climbing (n=5), and non-overhead athletes group n=30, participating in sports: track and field (n=6), gymnastics (n=12), skeleton (n=4) luge(n=8). Bilateral AROM for external rotation (ER) and internal rotation (IR) in the shoulder was measured with EasyAngle goniometer (Sweden). Isometric strength (IS) was measured for ER and IR with EasyForce dynamometer (Sweden). Parameters of AROM shoulder were calculated glenohumeral IR deficit (GRID), glenohumeral ER gain, (GER Gain), total arc of motion (TAM) and total range of motion deficit (TRMD). RESULTS: Results presented significant differences for overhead athletes have significantly greater AROM comparing to non-overhead athletes with differences IR of shoulder dominant side 7.69 p<.05, non-dominant 6.56 p<.05 and shoulder ER in dominant side 21.3 p<.001 and 13 p<.001 in non-dominant side . Significant differences were found in TAM for both dominant 29.0 p<.001 and non-dominant side 19.5 p<.001. Even with GER gain of 8.31 p<.001 for overhead athletes TRMD comes negative -9.44 p<.01 for overhead female athletes comparing to non-overhead athletes CONCLUSION: The results of this study showed the differences in shoulder AROM and strength imbalances in overhead female athletes during preseason testing. Professionals working with female youth overhead athletes should address significant AROM and strength deficiencies to reduce injury risks. References: 1. Oliver GD, Downs JL, Barbosa GM, Camargo PR. Descriptive Profile of Shoulder Range of Motion and Strength in Youth Athletes Participating in Overhead Sports Int J Sports Phys Ther. 2020 Dec;15(6):1090-1098. 2. Lau R, Mukherjee S. Prevalence of Shoulder and Elbow Overuse Injuries Among Competitive Overhead Youth Athletes in Singapore. Orthop J Sports Med. 2023 Mar 21;11(3)
Read CV Luisa DombrovskaECSS Paris 2023: OP-MH09
INTRODUCTION: During the menstrual cycle (MC), the fluctuation of 17-ß estradiol (E2) and progesterone (P4), may affect protein metabolism and training adaptations. This study assessed the effects of E2 and P4 and their combinations A.) on myotube diameter and total protein metabolism and molecular mechanisms in differentiated C2C12 myotubes, and B.) through a human intervention study, which analyzed how young women respond to high-volume weight training performed either in the follicular or luteal phase of the MC. METHODS: A.) Differentiated C2C12 cells were treated with different doses and combinations of E2 and P4. After 3 days of treatment cells were fixed and protein and RNA were extracted. Myotube diameter, protein synthesis rate and the expression of genes of mechanistical interest was analyzed. B.) 12 young women (31,8 ± 3 years, 64,4± 10 kg, 171,2± 7 cm) were randomly assigned to high-volume training in the follicular phase (HVF) or luteal phase (HVL). The HVF group trained four days a week until ovulation occurred, and their volume was reduced to two training sessions a week till menstruation. The HVL group trained in the opposite direction. The MC was monitored via cycle diary, ovulation test and of E2 and P4 saliva concentrations. The training program included squats, deadlifts, bench presses and rows. Every four weeks, strength performance (1RM) was assessed and body composition was evaluated. Nutrition was standardized and monitored via FDDB Explorer. RESULTS: A.) E2 treatment, in contrast to P4, led to a significant increase in myotube diameter (+40% E2: 1.26±0.11 vs P4: 0.86±0.06; p<.05) and total protein content (+11%, E2: 1.13±0.04 vs P4: 1.02±0.09; p=0.2). These effects could be counteracted by P4. E2, but not P4 treatment, results in an increase of the expression of myosin heavy chain and insulin-like growth factor-1 protein expression. Also, these effects were antagonized by P4. The expression of relevant geness show a comparable regulation. B.): So far, 5 female athletes completed the study. Initial results show significant increases in squat (+15,4 ± 7,7kg) and bench press (7,0 ± 2,9kg) performance as well as an increase in fat-free mass (Δ+1.4 ± 1.8kg; p=0,07), muscle mass (∆+1.8 ± 1.1kg; p<.01) and thigh circumference (right: Δ+2.4 ± 1.2cm; p<.05; left: Δ+2.1 ± 1.1; p=.09) The available data show no differences between the training response in the follicular phase (HVF) or luteal phase (HVL). Study is ongoing. CONCLUSION: Our in vitro data demonstrate an anabolic effect of E2 in C2C12 myotubes, which is counteracted by P4. This finding provides mechanistic evidence that hypertrophy training may be more effective during the follicular phase compared to the luteal phase, where progesterone levels increase significantly. Preliminary results from our training study in female athletes align with strength performance data; however, due to the low number of participants who completed the study, show no significant differences between the HVF and HVL groups thus far.
Read CV Patrick DielECSS Paris 2023: OP-MH09
INTRODUCTION: Blood flow restriction (BFR) training usually combines low-load (LL) resistance exercise with vascular occlusion, leading to strength and hypertrophy adaptations similar to or even exceeding those of conventional strength training [2]. However, despite its benefits, concerns remain about exercise-induced muscle damage (EIMD) from BFR training due to mixed findings [2]. The potential for increased EIMD is plausible, as metabolic stress can trigger various interlinked mechanisms leading to muscle cell damage or amplify mechanically induced muscle damage [1]. The applied arterial occlusion pressure (AOP) is a key factor influencing metabolic stress and therefore potentially EIMD. However, its relationship with EIMD near muscle failure remains unexplored. This study investigates how different occlusion pressures affect EIMD compared to free-flow training METHODS: This double-blind, randomized controlled trial examined EIMD across different AOPs in 40 participants, divided into 4 groups: no pressure (NP), low pressure (LP; 50% AOP), medium pressure (MP; 75% AOP), and high pressure (HP; 100% AOP). Participants performed unilateral knee extensions at 30% 1RM up to a maximum of 4 sets of 20 repetitions or until failure. Oxygen saturation (SmO2), respiratory exchange ratio (RER), lactate concentration, perceived exertion, and thermographic images were assessed. EIMD was primarily evaluated by isokinetic peak torque change 24h post-exercise (Δ24h), with secondary markers including pain (VAS), blood markers (CK, MB), swelling, stiffness, contractility, and skin temperature. Measurements were taken before, and at 1h, 24h, 48h, and 72h post-exercise. A one-way ANOVA analyzed strength changes (Δ24h-baseline) and acute exercise responses. Repeated measures ANCOVAs examined secondary markers over time. RESULTS: NP (74±9) and LP (67±15) groups completed more repetitions than MP (42±7) and HP (39±2). HP showed greater ΔSmO2 decrease (-55±24%) and higher ΔRER (64±20%) than NP (-19±22%). Perceived exertion was higher in MP (18±1) and HP (19±1) compared to NP (16±2), but lactate and skin temperature did not differ. NP had greater strength reduction than MP (MD=-9.95, p=0.045, 95%CI [-19.7, -0.2]) and HP (MD=-10.51, p=0.038 95%CI [-20.5, -0.5]). NP had higher VAS scores than MP and HP over time [F(6.29, 71.34) = 2.24, p = .046]. CONCLUSION: Our findings support the safety of BFR training, as EIMD did not exceed levels observed in conventional training. LP BFR resulted in similar EIMD to unrestricted training, while MP and HP led to even lower strength loss and DOMS. However, AOPs above 75% reduced mechanical load, potentially limiting long-term adaptations. LP preserved mechanical load while reducing training duration, making it a safe and time-efficient option. [1] Behringer et al., 2014 Exhaustive exercise-a near death experience for skeletal muscle cells? [2] Queiros et al., 2021. Effect of resistance training with blood flow restriction on muscle damage markers in adults: A systematic review.
Read CV Kevin HappECSS Paris 2023: OP-MH09