ECSS Paris 2023: CP-AP19
INTRODUCTION: Concussions are a significant health risk in high school American football, given their potential to cause both immediate and long-term neurological impairments. As awareness of concussion risks increases, there is a pressing need to develop and implement effective prevention strategies to safeguard young athletes. The neck plays a crucial role in stabilizing the head during impacts, and emerging research suggests that strengthening neck muscles may reduce the risk of concussion by limiting excessive head movement during collisions [1,2,3]. This study investigates the effect of neck strengthening exercises on concussion incidence among high school American football athletes over the 2022-2024 seasons. The primary objective is to determine whether incorporating neck exercises can reduce concussion rates, thereby supporting their integration into high school football training programs. METHODS: Certified Athletic Trainers (ATCs) affiliated with a California State University campus were recruited. Inclusion criteria required ATCs to be 25-65 years old, have 3 years of concussion data (covering the 2022-2024 seasons), and work with a high school American football team. Data were collected via a Qualtrics XM survey reporting physician-confirmed concussions, athlete numbers, athletic exposures (scrimmages, practices, games), and use of neck strengthening exercises during the 2022-2024 seasons; athletes with recent or ongoing concussion symptoms were excluded. One school served as a control without neck exercises, while 3 schools implemented neck training using weighted cervical movements, resistance-based exercises, or Iron Neck equipment with school-specific protocols. RESULTS: Schools implementing neck strengthening programs reported consistently lower concussion rates compared with the school without neck exercises across the 2022-2024 seasons. In 2022, concussion rates ranged from 2.9-4.0% at schools with neck exercises versus 14.2% at the control school. Similar trends were observed in 2023 (1.9-5.8% vs. 15.0%) and 2024 (2.6-8.3% vs. 14.2%). Concussion incidences included scrimmages, games, and practices, consistently lower at schools with neck exercise programs. CONCLUSION: Preliminary findings suggest that neck strengthening exercises may contribute to reduced concussion rates in high school American football athletes. However, variability across schools and potential confounding factors such as protective gear, exercise type, athlete conditioning, and coaching style, warrant cautions interpretation. Larger, controlled studies incorporating standardized neck interventions and objective neck strength assessments are needed to clarify the role of neck strengthening in concussion prevention. References 1) Eckner et al, AM J Phys Med Rehabil, 2018. 2) Felix et al, J Sci Med Sport, 2024. 3) Whittaker et al, J Orthop Sports Phys Ther, 2023.
Read CV KyungMo HanECSS Paris 2023: CP-AP19
INTRODUCTION: Classical threshold concepts (VT1/VT2; lactate thresholds) are typically derived from incremental laboratory protocols, yet team-sport reality includes disruptor bouts and a reversed (decreasing-intensity) workload structure. We hypothesized that lactate alone becomes non-informative during field recovery kinetics, whereas acid–base and blood-gas logistics better and faster track substrate switching and recovery biology. METHODS: Thirty-eight elite American football players (EFL) completed a standardized postprandial, field-ready performance test: mixed meal + digestion, then an in-lab stepwise warm-up and incremental YMCA protocol, immediately followed by a 1-min “disruptor” all-out bout. The subsequent field phase was intentionally reversed (decremental): high-demand mixed drills/CrossFit-type work transitioned to lower-intensity aerobic running, then stretching and passive recovery, reflecting match-like load followed by progressive unloading. Venous samples were repeatedly obtained via cannula and analyzed point-of-care for pH (H⁺ load), pO₂, pCO₂ and lactate. Indirect calorimetry quantified substrate kinetics (FFA contribution). RESULTS: A key marker finding was threshold-equivalent lactate under two physiologically different conditions: YMCA vs the field aerobic-run phase (YMCA: 5.95 ± 1.78 vs aerobic run: 6.24 ± 1.98 mmol·L⁻¹, NS). Despite similar lactate, the accompanying regulatory milieu diverged: Acid–base/H⁺: YMCA H⁺ 5.33 ± 0.82 nmol·dL⁻¹ (≈pH 7.27) vs aerobic run H⁺ 4.59 ± 0.53 (≈pH 7.34), p<0.001. O₂–CO₂ clearance: pO₂/pCO₂ YMCA 0.79 ± 0.37 vs aerobic run 0.97 ± 0.41, p<0.001. Substrate kinetics: FFA utilization YMCA 12.66 ± 11.14% vs aerobic run 31.10 ± 13.66%, p<0.001. CO₂ elimination showed a FEtCO₂ plateau, whereas O₂ availability remained intensity-dependent (as indicated by SmO₂), shaping the pO₂/pCO₂ response and aligning with higher field CHO reliance (HIF-1α–linked) despite unchanged lactate. Insulin increased during passive recovery vs aerobic run (p<0.01) despite a parallel elevation in whole-body FFA utilization, supporting dissociation of hormonal control from substrate oxidation. CONCLUSION: In a field-realistic, reversed workload sequence, lactate can remain “high/threshold-like” while pH/H⁺, pO₂/pCO₂, and fat utilization normalize; thus, lactate becomes a false state marker of metabolic readiness after disruptor bouts. Recovery should be interpreted through integrated O₂/CO₂ logistics and acid–base control: intensity-dependent reductions in O₂ availability likely destabilize HIF-1α–linked regulation and promote higher CHO reliance even at similar lactate. Active (low-intensity) vs passive recovery represents a metabolic divergence: active recovery sustains oxidative flux and lactate reutilization in local muscles (via monocarboxylate transporter 1, MCT1) and supports by-product handling, whereas passive recovery favors persistence of uncoupling. This marks the distinction between fatigue accumulation and adaptation.
Read CV Gabor KurucsaiECSS Paris 2023: CP-AP19
INTRODUCTION: Exploration of the match physical activity of elite junior ice hockey players, using global positioning system (GPS) and inertial measurement unit (IMU), has been the subject of very few studies. The objectives of this study are two-fold: 1- Quantify the external demands of elite junior ice hockey players using wearable technologies, and 2- verify the presence of differences in regard with three contextual aspects of the game: teams, positions and match outcomes. METHODS: Data is drawn from 64 Canadian junior elite males (20 defense, 34 forwards; 18 ± 1.5 yrs., 82.9 ± 5.7 kg, 181.1 ± 5.2 cm), competing from four different Quebec Maritimes Junior Hockey League (QMJHL) teams playing against each other, during a 4-day tournament held in an outdoor ice rink. Each athlete volunteer to participate wore a S7 Catapult GPS device in a harness. Measures included volume-based (total skating distance, relative velocity zones distances, number of accelerations, decelerations, changes of direction and total workload), intensity-based (peak skating velocity, peak acceleration and deceleration, peak workload, high force strides, force per stride), and density-based metrics (all variables expressed per minute of time on ice). Regression analyses were conducted to compare the difference between teams, playing positions, and match scoreboard. RESULTS: Players covered 5065 ± 1231m over the course of the four matches, in which 1187 ± 401m were achieved in the high velocity zone, produced 155 ± 42 total accelerations and decelerations, achieved a total workload (PlayerLoadTM) of 238 ± 45 u.a, a SkatingLoad of 1786 ± 441 u.a and an On-Ice Load of 139 ± 34 u.a. The average maximal skating velocity reached was 8.5 ± 0.5 m.s-1, achieved 20.7 ± 7.7 sprint efforts, and 10% of the total strides were considered high force strides. Forwards reached higher intensity and density-based metrics than defensemen (p < 0.05), while defensemen achieved greater volume-based metrics (p < 0.05). Correlations were found between the match outcome and some physical demands results (p < 0.05). Also, correlations were identified between the team in which players are competing and the some of the match activity physical data, especially intensity and density metrics (p < 0.05). CONCLUSION: This was the first study to measure match physical demands of elite junior ice hockey players with GPS implementation in an outdoor ice rink context. Players had a similar high external load during games compared to other studies, with a low to moderate variation of some volume or intensity-based variables. However, density metrics showed moderate to high variability, depending on the time-on-ice calculation method. Findings emphasize the relevance of selecting the more accurate metrics and considering the positional differences as well as result outcome when evaluating on-ice performance physical activity to better give an overview of the results.
Read CV Gaëtan MARTINIECSS Paris 2023: CP-AP19