European Journal of Sport Science

Alway, Peter; Wedatilake, Thamindu; Peirce, Nicholas; Warren, Anna; King, Mark; Brooke-Wavell, Katherine

doi: 10.1080/17461391.2022.2065929pmid: 35414351

The aim of this study is to determine if bone mineral density (BMD) and bone asymmetry differs between female cricket fast bowlers, spin bowlers and batters. BMD was determined at the total body, lumbar spine, and proximal femurs in 12 fast bowlers, 13 batters and 11 spin bowlers from pre-season DXA scans. High Z-scores at the total body, lumbar spine, and proximal femur were observed in all cricketers (mean Z-scores: +1.4 to +3.3) compared with a general age matched reference population. Fast bowlers had significantly greater BMD on the contralateral side of the lumbar spine compared with the ipsilateral side (p = 0.001, 5.9–12.1%). No asymmetry was found between hips in all groups. All cricket positions demonstrated high BMD at all measured sites. The lumbar spine of fast bowlers is asymmetric, with significantly greater BMD on the contralateral side of the spine, particularly at L4, possibly in response to the asymmetric lumbar loading patterns observed in bowling. Highlights Elite female cricketers demonstrate high BMD at total body, lumbar spine and proximal femur sites, regardless of playing position compared with a general age and ethnic group matched reference population. Fast bowlers have greater BMD on the contralateral (opposite bowling arm) side of the lumbar spine compared with the ipsilateral side, while a symmetrical pattern was observed in spin bowlers and batters. No asymmetry in BMD or section modulus between hips was observed at any proximal femur site for any cricket position.

Delorme, Julien; Blache, Yoann; Degot, Matthieu; Rogowski, Isabelle

doi: 10.1080/17461391.2022.2069511pmid: 35446227

The aim was to investigate the effects of sex, age, preferred judo technique, dominance, and injury history on the shoulder functional status of elite judo athletes. Sixty-one elite judo athletes (38 males, age: 18.1 ± 1.2 years, body mass: 69.3 ± 13.3 kg, body height: 172.2 ± 9.8 cm, brown belt to second-degree black belt) completed three questionnaires: Western Ontario Shoulder Instability, Western Ontario Rotator Cuff, and Shoulder Instability-Return to Sport after Injury. They performed four physical tests: the glenohumeral rotator isometric strength test, upper quarter Y-balance test, unilateral seated shot put test, and modified Closed Kinetic Chain Upper Extremity Stability Test. The results showed that the female athletes had less shoulder functional abilities than the male athletes (p < 0.001 to p = 0.02). The younger athletes had poorer shoulder stability and upper extremity power than the older athletes (p < 0.001 to p = 0.02), but their glenohumeral muscles were stronger in both internal (p = 0.03) and external (p = 0.005) rotations. All the judo athletes had similar bilateral differences in shoulder functional status, except for judokas who preferred throwing techniques (p = 0.01). Injury history affected self-perceived functional status (p < 0.001), as well as upper extremity muscle capacity and neuromuscular control (p = 0.01 to p = 0.05). This study provides new insight into the shoulder functional status of elite judo athletes, which may aid in the development of sports-specific injury prevention and return-to-sport programmes to reduce the risk of shoulder injury occurrence and recurrence. Highlights Normalized levels of upper extremity abilities must be sex- and age-specific in prevention programmes. Prevention programmes may focus on muscle bilateral and anteroposterior symmetry. Prevention programmes may include psychological training tailored to the sex of judo athletes.

DiFabio, Melissa S.; Smith, Daniel R.; Breedlove, Katherine M.; Pohlig, Ryan T.; Buckley, Thomas A.; Johnson, Curtis L.

doi: 10.1080/17461391.2022.2069512pmid: 35466861

Sustaining sports-related head impacts has been reported to result in neurological changes that potentially lead to later-life neurological disease. Advanced neuroimaging techniques have been used to detect subtle neurological effects resulting from head impacts, even after a single competitive season. The current study used resting-state functional magnetic resonance imaging to assess changes in functional connectivity of the frontoparietal network, a brain network responsible for executive functioning, in collegiate club ice hockey players over one season. Each player was scanned before and after the season and wore accelerometers to measure head impacts at practices and home games throughout the season. We examined pre- to post-season differences in connectivity within the frontoparietal and default mode networks, as well as the relationship between the total number of head impacts sustained and changes in connectivity. We found a significant interaction between network region of interest and time point (p = .016), in which connectivity between the left and right posterior parietal cortex seed regions increased over the season (p < .01). Number of impacts had a significant effect on frontoparietal network connectivity, such that more impacts were related to greater connectivity differences over the season (p = .042). Overall, functional connectivity increased in ice hockey athletes over a season between regions involved in executive functioning, and sensory integration, in particular. Furthermore, those who sustained more impacts had the greatest changes in connectivity. Consistent with prior findings in resting-state sports-related head impact literature, these findings have been suggested to represent brain injury. Highlights Functional connectivity of the frontoparietal network significantly increased between the pre- and post-season, which may be a compensatory mechanism driven by neural tissue injury caused by repetitive head impacts. Changes in frontoparietal network connectivity are related to head impact exposure, measured as the number of head impacts sustained in a single season. Functional connectivity of the default mode network did not change over an ice hockey season.

Hext, Andrew; Hettinga, Florentina Johanna; McInerney, Ciarán

doi: 10.1080/17461391.2022.2069513pmid: 35446752

In short-track speed skating, tactical positioning is essential for success as the race format (head-to-head) prioritises finishing position over finishing time. At present, our understanding of this phenomenon is based on measuring the similarity between athletes’ intermediate and final rankings. However, as this approach groups athlete performances across races, each lap’s estimate of tactical importance ignores the athlete-opponent interactions specific to each race. Here, we examine the utility of race-specific athlete-opponent interactions for investigating tactical positioning. Using intermediate and final rankings of elite 1,000 m short-track speed skating competitors collected from 2010/11–2017/18 (n = 6,196, races = 1,549), we compared the current method to a novel approach that accounted for race-specific athlete-opponent interactions. This approach first applied the current method to each race independently before using these values to form (1) discrete, empirical distributions of each lap’s tactical importance and (2) race-specific tactical positioning sequences. Our results showed that accounting for race-specific athlete-opponent interactions provided a higher measurement granularity (i.e. level of detail) for investigating tactical positioning in short-track speed skating, which better captured the complexity of the phenomenon. We observed 61 different tactical positioning behaviours and 1,269 unique tactical positioning sequences compared to the current approach’s nine-point estimates of tactical positioning importance. For this reason, we recommend that researchers and practitioners account for race-specific athlete-opponent interactions in the future as it offers a deeper understanding of tactical positioning that will enhance both strategic and tactical decisions. Highlights We compare the current approach for investigating tactical positioning to a novel approach that accounts for race-specific athlete-opponent interactions. We show that accounting for race-specific athlete-opponent interactions provides a higher measurement granularity (i.e. level of detail) for investigating tactical positioning in short-track speed skating. We demonstrate that this increased measurement granularity can facilitate a deeper understanding of tactical positioning by (1) producing theoretically-more-correct point estimates of tactical positioning importance, (2) enabling more rigorous statistical analyses into the effect of athlete-environment interactions on tactical positioning behaviour, and (3) allowing sequential analyses that capture the progressive relationships between laps. We recommend that researchers and practitioners account for race-specific athlete-opponent interactions in future investigations, as the findings will enhance analyst, coach, and athlete preparation for the strategic and tactical decision-making process essential for success in short-track.

Heinrich, Dieter; van den Bogert, Antonie J.; Nachbauer, Werner

doi: 10.1080/17461391.2022.2064770pmid: 35400304

Competitive skiers encounter a high risk of sustaining an ACL injury during jump-landing in downhill ski racing. Facing an injury-prone landing manoeuvre, there is a lack of knowledge regarding optimum control strategies. So, the purpose of the present study was to investigate possible neuromuscular control patterns to avoid injury during injury-prone jump-landing manoeuvres. A computational approach was used to generate a series of 190 injury-prone jump-landing manoeuvres based on a 25-degree-of-freedom sagittal plane musculoskeletal skier model. Using a dynamic optimization framework, each injury-prone landing manoeuvre was resolved to identify muscle activation patterns of the lower limbs and corresponding kinematic changes that reduce peak ACL force. In the 190 injury-prone jump-landing simulations, ACL forces peaked during the first 50 ms after ground contact. Optimized muscle activation patterns, that reduced peak ACL forces, showed increased activation of the monoarticular hip flexors, ankle dorsi- and plantar flexors as well as hamstrings prior to or during the early impact phase (<50 ms). The corresponding kinematic changes were characterized by increased hip and knee flexion and less backward lean of the skier at initial ground contact and the following impact phase. Injury prevention strategies should focus on increased activation of the monoarticular hip flexors, ankle plantar flexors and rapid and increased activation of the hamstrings in combination with a flexed landing position and decreased backward lean to reduce ACL injury risk during the early impact phase (<50 ms) of jump landing. Highlights First study investigating advantageous control strategies during injury-prone jump-landing manoeuvres in downhill skiing using a musculoskeletal simulation model and dynamic optimization framework. The simulation results predicted high injury risk during the first 50 ms after initial ground contact. Optimized neuromuscular control patterns showed adapted activation patterns (timing and amplitude) of muscles crossing the knee as well as the hip and ankle joints prior to and after initial ground contact, respectively. An optimized control strategy during an injury-prone landing manoeuvre was characterized kinematically by increasing hip and knee flexion and less backward lean of the skier at initial ground contact and the following impact phase.

Barreto, G.; Loureiro, L. M. R.; Reis, C. E. G.; Saunders, B.

doi: 10.1080/17461391.2022.2049885pmid: 35239468

The aim of this systematic review with meta-analysis was to determine the effect of caffeine gum (Caff-gum) on exercise performance-related outcomes. Several databases were searched for studies assessing the effect of Caff-gum in placebo-controlled protocols involving healthy adults. Random-effects meta-analyses using standardized mean differences (SMD) were performed to determine the effect of Caff-gum on exercise outcomes with several sub-analyses (training status, exercise type, timing and dose) for potential modifying factors. 14 studies were included, totalling 200 participants. There was a significant overall effect of Caff-gum compared to placebo (SMD = 0.21, 95%CI: 0.10–0.32; p = 0.001). Subgroup analysis showed improved performance for trained (SMD = 0.23, 95%CI: 0.08–0.37; p = 0.004), but not for untrained (SMD = 0.14, 95%CI: −0.02–0.29; p = 0.07) individuals. Caff-gum improved both endurance (SMD = 0.27, 95%CI: 0.12–0.42; p = 0.002) and strength/power (SMD = 0.20, 95%CI: 0.03–0.37; p = 0.03) performance outcomes. Caff-gum was ergogenic when consumed within 15 min prior to initiating exercise (SMD = 0.27, 95%CI: 0.07–0.4; p = 0.01), but not when provided >15 min prior (SMD = −0.48, 95%CI =  −1.7–0.82; p = 0.25). There was no significant effect of Caff-gum with doses <3 mg/kg body mass (BM) (SMD = 0.20, 95%CI: −0.03–0.43; p = 0.07), but there was a significant effect when the dose was ≥3 mg/kg BM (SMD = 0.22, 95%CI: 0.07–0.37; p = 0.01). Caff-gum supplementation may be an effective ergogenic strategy for trained athletes involved in both endurance and strength/power exercise, using a recommended dose of ≥3 mg/kg BM consumed within 15 min of initiating exercise. Highlights This study determined the effect of Caff-gum on exercise performance, using a systematic review and meta-analysis. Fourteen studies, totalling 200 participants performing a variety of endurance and strength/power exercise tests were included. The relative Caff-gum dose ranged from 1.27-4.26 mg/kg BM and timing ranged from 120 min prior to exercise up to intra-test application. Caff-gum was shown to be an effective ergogenic aid for trained individuals involved in both endurance and strength/power exercise. Supplement dose and timing modified the efficacy of Caff-gum. Supplementation with Caff-gum was effective when provided in doses ≥3 mg/kg BM and within 15 min prior to initiating exercise. Trained endurance or strength/power athletes seeking to benefit from caffeine in the form of chewing gum should supplement within 15 min prior to initiating an exercise task, in doses ≥3 mg/kg BM.

Brazier, Jon; Antrobus, Mark R.; Herbert, Adam J.; Callus, Peter C.; Stebbings, Georgina K.; Day, Stephen H.; Heffernan, Shane M.; Kilduff, Liam P.; Bennett, Mark A.; Erskine, Robert M.; Raleigh, Stuart. M.; Collins, Malcolm; Pitsiladis, Yannis. P.; Williams, Alun G.

doi: 10.1080/17461391.2022.2053752

Pérez-Castilla, Alejandro; Quidel-Catrilelbún, Mauricio Elías Leandro; Rodríguez-Pérez, Manuel A.; García-Ramos, Amador

doi: 10.1080/17461391.2022.2054364pmid: 35290158

This study aimed to compare the maximal mechanical variables derived from the load-velocity (L-V) relationship and 2000-meter rowing ergometer performance between rowers of different age categories, and to identify the L-V relationship variables more closely related to 2000-meter rowing ergometer performance. Nineteen competitive rowers (15 males and four females) aged between 15 and 25 years were evaluated during the national 2000-meter rowing ergometer competition organised by the Chilean Rowing Federation. Thereafter, the L-V relationship variables (load-axis intercept [L 0], velocity-axis intercept [v 0], and area under the L-V relationship line [A line]) were determined on separate occasions during the squat jump and prone bench pull exercises. Rowers were classified according to their chronological age for comparative purposes (under 16 years [U16] vs. over 16 years [O16]). L 0 and A line were always higher for O16 than for U16 (p ≤ 0.046; ES range = 0.99–1.79), while v 0 was generally comparable for both age categories (p ≥ 0.038; ES range = 0.07–1.03). Furthermore, the O16 revealed a greater performance (i.e. shorter total time) during the 2000-meter rowing ergometer competition (p = 0.011; ES = −1.31). In general, significant correlations were obtained between rowing performance and the L-V relationship variables obtained during the squat jump (r or ρ range = −0.294 to −0.922) and prone bench pull (r or ρ range = −0.322 to −0.928). These results support the L-V relationship as a sensitive procedure to evaluate the maximal mechanical capacities of lower- and upper-body muscles in competitive rowers. Highlights The load-velocity relationship variables are sensitive enough to differentiate between rowers of different age categories (U16 vs. O16). The load-velocity variables are significantly associated with 2000-meter rowing ergometer performance (total time). This novel testing methodology can provide practitioners and coaches with a simpler and more precise alternative to comprehensively assess a rower's maximal neuromuscular profiles.

Houtmeyers, Kobe C.; Brink, Michel S.; Helsen, Werner F.; Haelewijn, Nicolas; Hagen, Michiel; Jaspers, Arne; Vanrenterghem, Jos

doi: 10.1080/17461391.2022.2060136pmid: 35348436

The rating of perceived exertion method (RPE) allows to describe training intensity in a single value. To better understand the underlying components, the separate rating of perceived breathlessness (RPE-B) and leg-muscle exertion (RPE-L) has been proposed. Here we hypothesised that the separation between the two components may (partly) be determined by the impacts on the lower extremities. In this study, we aimed to experimentally evaluate the differential effect of high versus low impact running and jumping on RPE-B and RPE-L in team sport activities by manipulating the movement strategy (heel strike and passive landing pattern versus forefoot strike and active landing pattern). Eighteen recreational team sport players participated in two submaximal tests consisting of a sequence of running and jumping bouts, whilst ground reaction forces (GRF) were collected. RPE-B and RPE-L data were collected after each bout using the CR100 scale. Paired-samples t-tests were used to analyse between-session differences in these variables. GRF analysis showed that absorption mechanics differed considerably between the two sessions. RPE-L was on average 6.50 AU higher in the low impact session (p = 0.006). However, RPE-B was also increased by 4.96 AU with low impact (p = 0.009). We conclude that the extent to which the lower extremities are being exposed to high or low impacts does not explain a possible separation between the two RPE types. Highlights The separate rating of the different underlying components of RPE (e.g. variables related to the cardiorespiratory and the muscular system) may provide more insight in the relationship between training load and training outcomes, which likely differs between these components. The findings of this study do not support the idea that the separation in rating between perceived breathlessness (RPE-B, cardiorespiratory) and leg-muscle exertion (RPE-L, muscular) is also rooted in the extent to which musculoskeletal structures in the lower extremities are being exposed to high or low impacts.

Smith, Nathan D. W.; Girard, Olivier; Scott, Brendan R.; Peiffer, Jeremiah J.

doi: 10.1080/17461391.2022.2062056pmid: 35400303

This study examined cardiovascular, perceptual and neuromuscular fatigue characteristics during and after cycling intervals with and without blood flow restriction (BFR). Fourteen endurance cyclists/triathletes completed four 4-minute self-paced aerobic cycling intervals at the highest sustainable intensity, with and without intermittent BFR (60% of arterial occlusion pressure). Rest interval durations were six, four and four minutes, respectively. Power output, cardiovascular demands and ratings of perceived exertion (RPE) were averaged over each interval. Knee extension torque and vastus lateralis electromyography responses following electrical stimulation of the femoral nerve were recorded pre-exercise, post-interval one (+1, 2 and 4-minutes) and post-interval four (+1, 2, 4, 6 and 8-minutes). Power output during BFR intervals was lower than non-BFR (233 ± 54 vs 282 ± 60 W, p < 0.001). Oxygen uptake and heart rate during BFR intervals were lower compared to non-BFR (38.7 ± 4.5 vs 44.7 ± 6.44 mL kg−1 min−1, p < 0.001; 160 ± 14 vs 166 ± 10 bpm, p < 0.001), while RPE was not different between conditions. Compared to pre-exercise, maximal voluntary contraction torque and peak twitch torque were reduced after the first interval with further reductions following the fourth interval (p < 0.001) independent of condition (p = 0.992). Voluntary activation (twitch interpolation) did not change between timepoints (p = 0.375). Overall, intermittent BFR reduced the mechanical and cardiovascular demands of self-paced intervals without modifying RPE or knee-extensor neuromuscular characteristics. Therefore, BFR reduced the cardiovascular demands while maintaining the muscular demands associated with self-paced intervals. Self-paced BFR intervals could be used to prevent cardiovascular and perceptual demands being the limiting factor of exercise intensity, thus allowing greater physiological muscular demands compared to intervals without BFR. Highlights The use of blood flow restriction (BFR) during self-paced intervals (at the highest perceived sustainable intensity) causes a reduction in power output, pulmonary oxygen uptake and heart rate compared with non-restricted self-paced intervals. Despite lower mechanical and physiological demands during BFR cycling, the magnitude and aetiology of neuromuscular fatigue were not different to intervals without BFR, indicating the internal muscular load during BFR was elevated and potentially equivalent compared to without BFR. Self-paced intervals could be a suitable model to prescribe aerobic BFR exercise as an adjunct training stimulus for endurance cyclists.