ECSS Paris 2023: OP-AP14
INTRODUCTION: Mental fatigue is characterised by feelings of tiredness, decreased motivation and a lack of energy, which can have adverse effects on subsequent cognitive, skilled and physical performance. Caffeine intake, in doses between 1-6 mg·kg-1, is widely known for its ergogenic properties and has been shown to enhance endurance and cognitive performance. While caffeine has been shown to enhance endurance performance under mental fatigue, its effects on rugby-specific performance remain unexplored. The purpose of the study was to describe the effects of mental fatigue on simulated rugby league performance and to determine the effects of caffeine supplementation in the presence of mental fatigue. METHODS: Ten male university rugby players (age = 23 ± 4 y, body mass = 81.2 ± 6.8 kg, stature = 1.79 ± 0.06 m, predicted maximal oxygen uptake [V̇O2max] = 51.1 ± 5.5 ml.kg-1.min-1) completed four trials of the rugby league movement simulation protocol for interchanged players (RLMSP-i) in a randomised, repeated measures, double-blind design. After baseline measurements, participants completed a control, mental fatigue, caffeine (5 mg.kg-1) and a placebo trial of the RLMSP-i, with 5-8 days between trials. Mental fatigue was induced using a cognitively demanding task (30 min incongruent Stroop). Throughout all protocols, movement characteristics using a GPS device, heart rate and rating of perceived exertion were recorded. Before, at half time and immediately after the protocol, reaction time and passing accuracy were measured. Subjective task load (NASA-TLX) was reported on completion of each trial. Data are presented as means ± SD and effect sizes (ES) ± 90% confidence intervals (CI). RESULTS: Completing a mentally demanding task increased participants’ subjective rating of mental fatigue (pre = 29 ± 25 AU; post = 55 ± 20 AU) immediately before completing a simulation protocol. Impairments in sprint speed (ES = -0.18; ±0.19), sprint to contact speed (ES = -0.20; ±0.27), high-intensity running (ES = -0.30; ±0.24), high metabolic power > 20 W·kg-1 (ES =-0.50; ±0.51) and time to complete a passing accuracy task (ES = 0.54; ±0.63) were observed after mental fatigue. Caffeine supplementation (5 mg.kg-1) attenuated several adverse effects of mental fatigue, with increased sprint speed (ES = 0.40; ±0.18), high-intensity running (ES = 0.50; ±0.53), high metabolic power > 20 W·kg-1 (ES = 0.33; ±0.38) and decreased time to complete a passing accuracy test (ES =-0.70; ±0.45). CONCLUSION: Mental fatigue affected the internal loads, external loads and skill performance during simulated rugby league match play that appear to be centrally regulated by a decreased motivation and increased perception of effort. However, a single dose of caffeine (5 mg.kg-1) taken 60 min before performance can attenuate several of these adverse effects, supporting its role as an effective countermeasure for mental fatigue-induced declines in team sport performance.
Read CV Tom MullenECSS Paris 2023: OP-AP14
INTRODUCTION: Minimal evidence supports the implementation of an individualised approach to menstrual cycle management in team sports, especially one that accounts for cycle variability. This study explored strength and power performance changes across the menstrual cycle and phases of hormonal contraceptive (HC) use over two cycles. METHODS: Fourteen professional female Australian footballers participated in a 13-week pre-season study, reporting daily symptom severity. Naturally menstruating athletes (AthletesNMC, n=7) completed countermovement jump relative peak power (CMJ RPP) and isometric belt squat relative peak force (IBSQ RPF) tests during menstruation (days 2–6 after bleeding onset), ovulation (within 48 hours of a positive ovulation test), and the luteal phase (7–9 days post-ovulation). Athletes using HC (AthletesHC, n=7) were tested during bleeding and across three arbitrary phases. Results are reported as 95% CI [upper limit, lower limit] RESULTS: Two athletes (IUD users) did not experience regular bleeding. Ovulation was confirmed in at least one cycle for all (14 ± 1.73 days) and across two cycles for three athletes. Two AthletesNMC were found to have progesterone levels (<16mmol/L) in the mid-luteal phase in one cycle but were (>16mmol/L) in the following cycle. Average bleed duration and cycle length were 4.5 ± 1.38 and 28.68 ± 5.06 days, respectively. Abdominal cramps were the most reported symptom (count=78). Daily symptom severity (SS) scores were significantly higher in HC users (p=0.004), with greater variability (SD = 4.33) compared to AthletesNMC (SD = 3.10). Peak SS occurred at different times (AthletesNMC: Day 2, 4.1 ± 8.4 AU; AthletesHC: Day 29, 3 ± 6 AU).Peak Power (CMJ RPP) (W/kg) results across the three phases in cycle 1 were 47.11 [45.16–49.07], 42.26 [38.75–45.76], and 44.79 [41.53–48.05], respectively. In cycle 2, these values were 43.50 [40.50–46.50], 41.34 [37.14–45.54], and 42.84 [40.14–45.54], respectively. A general decline in peak power is observed from cycle 1 to cycle 2 across phases, though the magnitude of change varies. Peak Force (ISBQ RPF) (N/kg) results in cycle 1 were 38.80 [33.60–43.99], 38.30 [32.61–43.98], and 36.18 [31.62–40.73], while in cycle 2, values were 39.29 [35.60–42.98], 44.70 [35.03–54.37], and 42.11 [36.40–47.82]. Peak force showed a more mixed trend, with values generally increasing in cycle 2, suggesting greater variability in force production across cycles. CONCLUSION: This study demonstrates the variability in strength and power performance measures across menstrual cycle phases and hormonal contraceptive use in elite female athletes. Moreover, this study showed variance in performance between consecutive cycles and daily symptom severity between athletes naturally menstruating compared with those on hormonal contraception. Practitioners working with female athletes should consider individualised approaches when working with female athletes.
Read CV Hannah MooreECSS Paris 2023: OP-AP14
INTRODUCTION: Running vertical jump is a fundamental movement pattern in various sports, particularly those requiring explosive takeoff, such as basketball layups, handball shooting and high jumping [1]. The effectiveness of approach distance in optimizing takeoff performance is influenced by multiple biomechanical factors, including takeoff technique, lower limb power and the conversion of horizontal velocity into vertical impulse. Moreover, variations in jumping mechanics between elite and general athletes may lead to distinct neuromuscular strategies. Therefore, this study aims to investigate the influence of different approach distances on lower-limb explosive force production and muscle activation during single-leg vertical jump, providing insight into the optimal approach strategy for maximizing performance. METHODS: This study recruited 24 healthy male athletes, divided into elite group and general group (12 participants each). Participants performed single-leg vertical jumps with approach distances of 1 m, 3 m, and 5 m. The study analyzed lower limb joint angles, muscle activation, initial eccentric rate of force development (IRFD), speed strength index (SSI), reactive strength index (RSI), and reactive strength ratio (RSR). Two-way ANOVA, mixed design was conducted to compare lower extremities parameters across distances and groups. RESULTS: The results indicated no significant difference in jump height across different approach distances. However, RFD, SSI, RSI and RSR were significantly higher in the 3 m and 5 m approaches compared to the 1 m approach (p = 000). Additionally, in the 3 m and 5 m approaches, the elite group exhibited significantly greater quadriceps activation and shorter contact time compared to the general group. The elite group also demonstrated less hip flexion (p = 000) and ankle dorsiflexion during takeoff (p = 000). CONCLUSION: The findings suggest that approach distance does not significantly affect jump height, but takeoff velocity varies with approach distance. Notably, the 3 m and 5 m approaches resulted in significantly shorter contact times compared to the 1 m approach, facilitating greater explosive force output and more efficient energy utilization. Furthermore, the elite group demonstrated quadriceps activation, which enhanced the stretch-shortening cycle (SSC) effect. In contrast, the general group compensated for technical deficiencies with greater hip flexion and ankle dorsiflexion, potentially reducing energy transfer efficiency and jump performance. These results suggest that elite athletes may generate higher horizontal velocity in longer approach distances, affecting vertical energy conversion. Ultimately, lower-limb strength and SSC optimization remain crucial determinants of jump performance across different approach distances. 1. Alemdaroğlu (2012)
Read CV Ting-Ming HsuECSS Paris 2023: OP-AP14