The intermittent activity profile of soccer match play increases the complexity of the physical demands. Laboratory models of soccer match play have value in controlled intervention studies, developed around manipulations of the activity profile to elicit a desired physiological or biomechanical response. Contemporary notational analyses suggest a profile comprising clusters of repeat sprint efforts, with implications for both biomechanical and physiological load. Eighteen male soccer players completed a 90-minute treadmill protocol based on clusters of repeat sprint efforts. Each 15-minute bout of exercise was quantified for uniaxial (medial-lateral [PLML], anterior-posterior [PLAP], and vertical [PLV]) and triaxial PlayerLoad (PLTotal). The relative contributions of the uniaxial PlayerLoad vectors (PLML%, PLAP%, and PLV%) were also examined. In addition to rating of perceived exertion, the physiological response comprised heart rate, blood lactate concentration, and both peak and average oxygen consumption. Triaxial PlayerLoad increased (p = 0.02) with exercise duration (T0-15 = 206.26 ± 14.37 a.u. and T45-60 = 214.51 ± 14.97 a.u.) and remained elevated throughout the second half. This fatigue effect was evident in both the PLML and PLAP movement planes. The mean relative contributions of PLV%:PLAP%:PLML% were consistent at ∼48:28:23. The physiological response was comparable with match play, and a similar magnitude of increase at ∼5% was observed in physiological parameters. Changes in PlayerLoad might reflect a change in movement quality with fatigue, with implications for both performance and injury risk, reflecting observations of match play. The high frequency of speed change elicits a 23% contribution from mediolateral load, negating the criticism of treadmill protocols as "linear."

Acute adaptations and subsequent preservation of strength and speed measures following a Nordic hamstring curl intervention: a randomised controlled trial. Journal of Sports Sciences, 37 (8). pp. 911-920.

Dance is associated with a high risk of injury and fatigue is often a contributing factor. The Star Excursion Balance Test (SEBT) has been used to identify alterations in normal movement that may contribute to injury risk; however, there has been limited investigation of the potential effects of fatigue. The aim of this study was to explore the influence of dance-specific fatigue on SEBT performance, with implications for injury and performance in dance. Thirty-five university dancers completed the modified SEBT in anterior, posterolateral, and posteromedial directions prior to and immediately following the Dance Aerobic Fitness Test (DAFT). The SEBT was completed for dominant and non-dominant legs. Heart rate and rate of perceived exertion were quantified as measures of fatigue. Post-DAFT, the mean SEBT percentage maximized reach distances for dominant and nondominant legs were non-significant compared to pre-DAFT scores. Lack of a main effect for exercise was observed in each of the anterior dominant and non-dominant, posterolateral dominant and non-dominant, and posteromedial dominant and non-dominant scores. It is concluded that the limited changes in the ability of dancers to perform the SEBT suggest that they were able to maintain SEBT performance in both dominant and non-dominant legs following exercise. This resistance to fatigue may demonstrate a dance-specific performance adaptation so that potential alterations in movement performance that may increase injury risk were not observed.

Injury incidence in dance is high, in large part due to the frequency of repetitive and complex movements that require the lower limb to absorb and utilize extreme forces. The aim of this study was to quantify the biomechanical demands of the Dance Aerobic Fitness Test (DAFT) via triaxial accelerometry and utilize it to compare loading at the cervical spine and distal aspect of the lower limb. University dancers (N = 26; age: 20.0 ± 1.5 years; height: 1.61 ± 0.08 m; body mass: 58.40 ± 6.20 kg) completed two trials (one familiarization and one experimental) of the DAFT, consisting of five incremental levels of dance performance. Micromechanical electrical systems (MEMS) accelerometry was used to calculate total accumulated PlayerLoad (PLTotal) and it's uniaxial (anteroposterior [PLAP], mediolateral [PLML], and vertical [PLV]) components for each level. MEMS units were positioned at cervical vertebra 7 (C7) and the center of gastrocnemius (LL). There was a significant main effect for each level, with loading increasing in relation to exercise duration. There was also a significant main effect for anatomical placement, with higher PLTotal (C7 = 41.05 ± 7.31 au; LL = 132.58 ± 35.70), PLAP (C7 = 12.96 ± 2.89 au; LL = 47.16 ± 13.18 au), and PLML (C7 = 10.68 ± 2.15; LL = 46.29 ± 12.62 au) at LL when compared to C7, with the converse relationship for PLV (LL = 20.05 ± 3.41 au; C7 = 44.89 ± 11.22 au). Significant interactions were displayed for all PL metrics. It is concluded that triaxial PlayerLoad was sensitive enough to detect increased loading associated with increases in exercise intensity, while lower limb accelerometer placement detected higher loading in all planes. The specificity in anatomical placement has practical implications, with lower limb accelerometry recommended to assess movement strategies in that location.

The aim of this study was to assess the physiological, perceptual, and mechanical measures associated with the completion of a simulated period of short-term soccer-specific fixture congestion. Ten male semi-professional soccer players completed three trials of a treadmill-based match simulation, with 48 hours intervening each trial. A repeated measures general linear model identified significantly (P= 0.02) lower knee flexor peak torque (PT) recorded at 300 degs[BULLET OPERATOR]s in the second (141.27 ± 28.51 Nm) and third trials (139.12 ± 26.23 Nm) when compared to the first (154.17 ± 35.25 Nm). Similarly, muscle soreness (MS) and PT data recorded at 60 degs[BULLET OPERATOR]s were significantly (P< 0.05) different in the third trial (MS= 42 ± 25 a.u; PT60= 131.10 ± 35.38 Nm) when compared to the first (MS= 29 ± 29 a.u; PT60= 145.61 ± 42.86 Nm). Significant (P= 0.003) differences were also observed for mean Bicep Femoris electromyography (EMGmean) between the third trial (T0-15= 126.36 ± 15.57 µV; T75-90= 52.18 ± 17.19 µV) and corresponding time points in the first trial (T0-15= 98.20 ± 23.49 µV; T75-90= 99.97 ± 39.81 µV). Cumulative increases in perceived exertion, heart rate, oxygen consumption, blood lactate concentrations, EMGmean, and PlayerLoad were recorded across each trial. MS and PT were also significantly different post-trial. There were however no significant main effects or interactions for the salivary Immunoglobulin A, and the medial-lateral PlayerLoad metrics. These data suggest a biomechanical and muscular emphasis with residual fatigue, with implications for injury risk and the development of recovery strategies.