• Acute effects of breaking up prolonged sedentary time on cardiovascular disease risk markers in adults with paraplegia

      Bailey, Daniel Paul; Withers, Thomas M.; Goosey-Tolfrey, Victoria L.; Dunstan, David W.; Leicht, Christof A.; Champion, Rachael B.; Charlett, Opie P.; Ferrandino, Louise; (John Wiley and Sons, 2020-04-03)
      Elevated levels of cardiovascular disease (CVD) risk markers are highly prevalent in people with a spinal cord injury (SCI). Breaking up prolonged sedentary time with short, regular bouts of physical activity can reduce postprandial glucose and lipid levels in able-bodied individuals. The effects in people with paraplegia are unknown. The study aims were to examine the acute postprandial glucose (primary aim), lipid, blood pressure, and psychological responses (secondary aims) to breaking up prolonged sedentary time in individuals with paraplegia. This was a randomized crossover design trial. Fourteen participants with paraplegia (age 51 +- 9 years, trunk fat mass 44.3 +- 7.7%) took part in the following two, 5.5-hour conditions: (1) uninterrupted sedentary time (SED), and (2) sedentary time interrupted with 2 minutes of moderate-intensity arm crank ergometer physical activity every 20 minutes (SEDACT). Standardized breakfast and lunch test meals were consumed during each condition. The outcomes were compared between conditions using linear mixed models. Glucose area under the curve (AUC) was significantly lower during the lunch postprandial period in SED-ACT vs SED (incremental AUC 1.9 [95% CI 1.0, 2.7) and 3.0 [2.1, 3.9] mmol/L∙2.5 hour, respectively, P = .015, f = 0.34). There were no differences between conditions for the breakfast or total 5.5 hours postprandial periods (P > .05). Positive affect was higher in SED-ACT than SED (P = .001). Breaking up prolonged sedentary time acutely attenuates lunch postprandial glucose and improves positive affect in people with paraplegia. This may have clinical relevance for reducing CVD risk and improving psychological well-being in this population.
    • The impact of playing in matches while injured on injury surveillance findings in professional football

      Hammond, Lucy E.; Lilley, J.M.; Pope, G.D.; Ribbans, W.J.; (Blackwell Munksgaard, 2013-10-10)
      This study aimed to analyze the frequency, nature, and consequences of footballers playing matches while injured, and to examine the impact on injury surveillance findings. High levels of inter-rater reliability and content validity were established for a tool designed to document players who were already injured at the start of a match. The tool was implemented in three English football teams (a Championship, League 1, and League 2 team) for one season, using a "time loss" definition of injury. One hundred forty-three matches were surveyed, revealing 102 match appearances by players who were already injured. Almost half of all games featured at least one injured player, with episodes of playing with injury occurring more frequently and lasting longer in League 2 players compared with higher level players. No association was observed between the number of injured players starting matches and match outcome [χ2(4, N=143)=3.27, P=0.514]. Fifteen percent of all injury episodes captured were only through prospective documentation of playing while injured. The findings show that both traumatic and overuse injuries are managed by footballers through competitive matches, and have important implications for aiding understanding of the epidemiology of injury in professional football..
    • Live high, train low - influence on resting and post-exercise hepcidin levels

      Govus, Andrew; Peeling, P.; Abbiss, Chris R.; Lawler, N.G.; Swinkels, D.W.; Laarakkers, C.M.; Thompson, K.G.; Peiffer, Jeremiah J.; Gore, C.J.; Garvican-Lewis, L.A. (2016-03-31)
      ) was measured via CO rebreathing 1 week before and after 14 days of hypoxia. Hepcidin was suppressed after 2 (Cohen's d = -2.3, 95% confidence interval: [-2.9, -1.6]) and 14 days of normobaric hypoxia (d = -1.6 [-2.6, -0.6]). Hepcidin increased from baseline, 3 h post-exercise in normoxia (d = 0.8 [0.2, 1.3]) and hypoxia (d = 0.6 [0.3, 1.0]), both before and after exposure (normoxia: d = 0.7 [0.3, 1.2]; hypoxia: d = 1.3 [0.4, 2.3]). In conclusion, 2 weeks of normobaric hypoxia suppressed resting hepcidin levels, but did not alter the post-exercise response in either normoxia or hypoxia, compared with the pre-exposure response.
    • Running performance and thermal sensation in the heat are improved with menthol mouth rinse but not ice slurry ingestion

      Dascombe BJ; Stevens, C.J.; Thoseby, B.; Sculley, D.V.; Callister, R.; Taylor, Lee; ; University of Newcastle, Australia; University of Bedfordshire (Blackwell Munksgaard, 2015-09-26)
      The purpose of this study was to compare the effects of a cooling strategy designed to predominately lower thermal state with a strategy designed to lower thermal sensation on endurance running performance and physiology in the heat. Eleven moderately trained male runners completed familiarization and three randomized, crossover 5-km running time trials on a non-motorized treadmill in hot conditions (33 °C). The trials included ice slurry ingestion before exercise (ICE), menthol mouth rinse during exercise (MEN), and no intervention (CON). Running performance was significantly improved with MEN (25.3 ± 3.5 min; P = 0.01), but not ICE (26.3 ± 3.2 min; P = 0.45) when compared with CON (26.0 ± 3.4 min). Rectal temperature was significantly decreased with ICE (by 0.3 ± 0.2 °C; P < 0.01), which persisted for 2 km of the run and MEN significantly decreased perceived thermal sensation (between 4 and 5 km) and ventilation (between 1 and 2 km) during the time trial. End-exercise blood prolactin concentration was elevated with MEN compared with CON (by 25.1 ± 24.4 ng/mL; P = 0.02). The data demonstrate that a change in the perception of thermal sensation during exercise from menthol mouth rinse was associated with improved endurance running performance in the heat. Ice slurry ingestion reduced core temperature but did not decrease thermal sensation during exercise or improve running performance.
    • Vertical stiffness asymmetries during drop jumping are related to ankle stiffness asymmetries

      Maloney, Sean J.; Richards, Joanna C.; Nixon, Daniel G.D.; Harvey, Lewis J.; Fletcher, Iain M. (Wiley, 2016-03-31)
      Asymmetry in vertical stiffness has been associated with increased injury incidence and impaired performance. The determinants of vertical stiffness asymmetry have not been previously investigated. Eighteen healthy males performed three unilateral drop jumps during which vertical stiffness and joint stiffness of the ankle and knee were calculated. Reactive strength index was also determined during the jumps using the ratio of flight time to ground contact time. ‘Moderate’ differences in vertical stiffness (t17 = 5.49; P < 0.001), ‘small’ differences in centre of mass displacement (t17 = -2.19; P = 0.043) and ‘trivial’ differences in ankle stiffness (t17 = 2.68; P = 0.016) were observed between stiff and compliant limbs. A model including ankle stiffness and reactive strength index symmetry angles explained 79% of the variance in vertical stiffness asymmetry (R2 = 0.79; P < 0.001). None of the symmetry angles were correlated to jump height or reactive strength index. Results suggest that asymmetries in ankle stiffness may play an important role in modulating vertical stiffness asymmetry in recreationally trained males.