ECSS Paris 2023: OP-PN31
INTRODUCTION: Gaelic games match play consists of intervals of lower intensity activities including walking, jogging or standing interspersed with repeated high-intensity bouts which often leads to fatigue [1,2]. Despite this, no study has comprehensively investigated the effect of competitive match play on fatigue in female Gaelic games athletes. The purpose of this study was to examine the post-match changes in neuromuscular function following competitive female Gaelic games. METHODS: Twelve collegiate female Gaelic games players (age: 21±1 yrs, height: 170.5±4.5 cm; body mass: 66.2±8.1 kg) were recruited for this study. The following were collected pre- and post- competitive match, and again at 12h, 36h, and 60h post-match: reactive strength index (RSI), countermovement jumps (CMJ) and maximal isometric relative torque during knee extension (KE) and flexion (KF) paired with surface electromyography (eEMG), plasma interleukin-6 (IL-6) as well as Global positioning systems (GPS) recording match play. Data were analysed using one-way repeated measures ANOVA and paired T-tests to examine changes. RESULTS: The mean distance covered was 4812.5±1315.8 m. CMJ height decreased from immediately post- to 12h post-match (226.9±5.0 to 24.7±4.2 cm, P=0.006, ηp2= 0.356). Neither Vastus Lateralis (VL) or Biceps Femoris (BF) peak amplitude, RSI or KF changed over time (P>0.05). There was a main effect of time on KE (P=0.006), which decreased from 2.56±0.63 Nm.kg-1 post- to 2.25±0.62 Nm.kg-1 60h post-match (P=0.026), with a large effect (ηp2 = 0.274) and did not return to baseline (2.48±0.12 Nm.kg-1) at 60h post-match. There was a main effect of time on blood plasma IL-6 pg.mL-1 (P=0.019). IL-6 increased from 1.36±2.59 pre- to 3.91±3.26 pg.mL-1 post-match (P=0.030). IL-6 decreased from 3.91±3.26 post- to 0.95±1.60 pg.mL-1 12h post-match, with a large effect (ηp2 = 0.410), and remained at baseline until 60h post-match (P=0.448). CONCLUSION: This is the first study to identify the post-match changes in neuromuscular function following competitive collegiate female Gaelic games. The reductions in neuromuscular function up to 60h post-match, indicates the fatigue induced by female Gaelic games players. This is similar to male Gaelic games players who experience fatigue up to 48h post-match [3]. Although the systematic inflammation dissipates quickly (<12 h), the neuromuscular system remains suppressed until 36h and in some respects 60h, which has implications for training and match schedules where optimising performance is crucial. REFERENCES: 1. Reilly and Collins (2008). Science and the Gaelic sports: Gaelic football and hurling. European Journal of Sport Science, 8(5): 231-240 2. Reilly et al., (2015). Match-play demands of elite youth Gaelic football using global positioning system tracking. The Journal of Strength & Conditioning Research, 29(4): 989-996 3. Daly et al., (2020). Gaelic football match-play: performance attenuation and timeline of recovery. Sports, 8(12): p.166
Read CV Aoife RussellECSS Paris 2023: OP-PN31
INTRODUCTION: Muscle spindle stimulation with superimposed local vibration (SLV) revealed temporarily motor unit recruitment facilitation and increased strength during submaximal contraction (1). Conversely, repeated spindle activation during voluntary contractions reduces support to α-motoneurons, leading to fatigue and strength loss (2). Thus, applying SLV during fatiguing submaximal contractions may slow the decline in force (known as “performance fatigability”). This study examined SLV effects during an intermittent, fatiguing knee extension task and explored its interaction with contraction intensity (low vs. moderate) and sex. METHODS: A total of 45 participants performed maximal voluntary contraction (MVIC) of the knee extensors and flexors before (PRE) and after (POST), a fatiguing task. The fatiguing protocol consisted of intermittent knee extensions (15s effort, 5s rest) at 50% (15 males and 9 females) or 30% MVIC (13 males and 8 females) until a 10% strength target loss. Participants realized the control task (CON) or the vibration condition (SLV) in random order. The vibration was applied to the quadricipital tendon (100 Hz, 2-3 mm). An ANOVA between Condition was used for the time to exhaustion (TTE) including statistical parameters Sex and Intensity (30% vs. 50%) as between-subject factors and Condition (CON vs. SLV) as a within-subject factor. Similar parameters were used for the MVIC using a two repeated factors ANOVA (Time [PRE vs POST] × Condition [CON vs SLV]). RESULTS: The MVIC decreased from PRE (240 ± 71 N∙m) to POST (164 ± 54 N∙m) similarly in both Condition (p = 0.834), Intensity (p = 0.948) or Sex (p = 0.147). The ANOVA revealed a longer TTE at 30% (274 ± 119s) than at 50% (112 ± 28s, p < 0.001) and Sex did not influence the TTE (p = 0.245). The analysis showed that SLV increased by 11 ± 21% the TTE (CON: 179 ± 110s, SLV: 196 ± 121s, p = 0.007) without differences between Intensity (p = 0.064) or Sex (p = 0.120). Finally, no correlation was found between the MVIC and the Condition (p = 0.815). CONCLUSION: We found that superimposed local vibration is an efficient method to increase the time before exhaustion at low or moderate intensity for males and females without altering the force loss after the fatiguing task. Moreover, its positive effect remains consistent regardless of maximal force, suggesting that SLVs influence is independent of individual strength levels. This leads us to ask how the chronic use of SLV during resistance strength training can influence performance? (1) Grande et al., “Ia afferent input alters the recruitment thresholds and firing rates of single human motor units”, Exp Brain Res, 2003. (2) Macefield et al., “Decline in spindle support to alpha‐motoneurones during sustained voluntary contractions”, J Physiol, 1990.
Read CV Tom TIMBERTECSS Paris 2023: OP-PN31
INTRODUCTION: The Arctic environment features various environmental challenges, such as extreme cold and hypoxia, could increase soldiers’ mental demand and impair soldiers’ cognitive performance in terms of accuracy and attention. The purpose of this study was to explore the effects of operating in a hypoxic and cold environment (HCE) on the cognitive functions of three different groups of alpine soldiers. METHODS: 34 soldiers specialized in mountain warfare (Alpine Corp) were tested before, during and after 3 days of military training (1-2-3/12 2024), on the Mont Blanc (3375m). Additional tests were conducted at 551m, four days before and 14 days after training. Soldiers were divided in 3 different groups, based on their experience and operational role: A (alpine lieutenant), B (alpine special forces), C (alpine specialized guides). Each day, soldiers were tested before and after the military operation session consisting of trekking and survival skills. Pre-operation measures included the Groningen Sleep Quality and the Fatigue scales, a 5-min psychomotor vigilance task (PVT), and a 5-min step test. After operating, soldiers repeated PVT and the step test. In addition, they rated the effort (session RPE), the workload (NASA-TLX) experienced during the operating session and the subjective fatigue changes compared to pre-military operation (Fatigability scale). Mixed ANOVAs were used to test the effects of Group, Day and, when relevant, Time. Significance was set at p<0.05. RESULTS: PVT performance deteriorated significantly after training only on the first day in HCE (p<0.05), indicating acute cognitive fatigability. Military training was perceived as more mentally demanding in HCE (p <0.05). Both fatigue and fatigability increased significantly in HCE (p <0.001). In addition, fatigability rating was the highest on the 1st day and then decreased, being significantly higher compared to 3rd day in HCE (p=0.002). Rating of sleep quality worsen at in HCE (p <0.001). No significant difference between groups. CONCLUSION: These results show that even soldiers specifically trained for mountain warfare suffer from the negative effects of HCE on cognitive performance, sleep perceived quality and general fatigue. There was no significant effects of HCE on cognitive performance before military operation, while after the operation cognitive performance decreased significantly especially on the first day in HCE, indicating a significant degree of cognitive fatigue induced by operating in hypoxia, cold and a challenging environment. Moreover, this military operation was perceived to be more mentally demanding and fatiguing in HCE compared to low altitude. Countermeasures for cognitive fatigue should be developed to improve soldiers’ performance, especially during the first day in HCE.
Read CV Sara SpinabelliECSS Paris 2023: OP-PN31