Kelly Marrin

Human Core Temperature Responses during Exercise and Subsequent Recovery: An Important Interaction between Diurnal Variation and Measurement Site

Chronobiological investigations into core temperature during and after exercise can involve ambulatory measurements of intestinal temperature during actual competitions, esophageal temperature measurements in laboratory simulations, or rectal temperature, which can be measured in both the field and laboratory. These sites have yet to be compared during both morning and afternoon exercise and subsequent recovery. At 08∶00 and 17∶00 h, seven recreationally active males exercised at 70% peak oxygen uptake for 30 min and then recovered passively for 30 min. During the experiment, esophageal, rectal, intestinal, and skin temperatures, plus sweat loss, heart rate, and ratings of perceived exertion (RPE), were monitored. We found that the diurnal variation in intestinal temperature responses (0.45±0.32°C; mean±SD) was significantly larger compared with rectal (0.33±0.24°C) and, particularly, esophageal temperature responses (0.21±0.20°C; p= 0.019). This reflected a greater difference of 0.25–0.40°C between the esophagus and the other two sites in the afternoon, compared to inter‐site differences of only 0.13–0.16°C in the morning. Diurnal variation was small for skin temperature, heart rate, sweat loss, and RPE responses during exercise (p>0.05). Our data suggest that the relative differences between intestinal, rectal, and esophageal temperature during exercise and subsequent recovery depend on time of day to the extent that inferences from studies on experimental and applied chronobiology will be affected.

Diurnal variation in vascular function: Role of Sleep

Although vascular function is lower in the morning than afternoon, previous studies have not assessed the influence of prior sleep on this diurnal variation. The authors employed a semiconstant routine protocol to study the contribution of prior nocturnal sleep to the previously observed impairment in vascular function in the morning. Brachial artery vascular function was assessed using the flow-mediated dilation technique (FMD) in 9 healthy, physically active males (mean ± SD: 27 ± 9 yrs of age), at 08:00 and 16:00 h following, respectively, 3.29 ± .37 and 3.24 ± .57 h prior sleep estimated using actimetry. Heart rate and systolic and diastolic blood pressures were also measured. The data of the experimental sleep condition were compared with the data of the “normal” diurnal sleep condition, in which FMD measurements were obtained from 21 healthy individuals who slept only during the night, as usual, before the morning test session. The morning-afternoon difference in FMD was 1 ± 4% in the experimental sleep condition compared with 3 ± 4% in the normal sleep condition (p = .04). This difference was explained by FMD being 3 ± 3% lower in afternoon following the prior experimental sleep (p = .01). These data suggest that FMD is more dependent on the influence of supine sleep than the endogenous circadian timekeeper, in agreement with our previous finding that diurnal variation in FMD is influenced by exercise. These findings also raise the possibility of a lower homeostatic “set point” for vascular function following a period of sleep and in the absence of perturbing hemodynamic fluctuation. (Author correspondence: h.jones1@ljmu.ac.uk)

Comparison of Two Anaerobic Water Polo-Specific Tests With the Wingate Test

Bampouras, TM and Marrin, K. Comparison of two anaerobic water polo-specific tests with the Wingate test. J Strength Cond Res 23(1): 336-340, 2009-The purpose of the current study was to compare 2 water polo-specific tests-the 14 × 25-m swims (SWIM) and the 30-second crossbar jumps (30CJ)-with a laboratory-based test of anaerobic power, the Wingate Anaerobic Test (WAnT). Thirteen elite womens water polo players (mean ± SD: age 22.0 ± 4.4 years, height 168.7 ± 7.9 cm, body mass 65.9 ± 6.1 kg, body fat 23.6 ± 3.5 %, maximum oxygen uptake 51.4 ± 4.5 ml·kg−1·min−1) participated in the study. The SWIM involved 14 repeated “all-out” sprints every 30 seconds. Swimming time was recorded, and sprint velocity, mean velocity (Vmean), and the gradient of the linear regression equation (GRADIENT) were calculated. The 30CJ involved repeated in-water water polo jumps and touching the goal crossbar with both hands. The number of touches in 30 seconds was recorded. Additionally, the subjects completed a 30-second WAnT, and mean power (Mp) and fatigue index (FI) were calculated. Kendall tau (τ) rank correlation was used to examine for correlation between ranks. Significance level was set at p ≤ 0.05. No significant correlation was found between any of the measures of the WAnT and the 2 sport-specific tests. It was suggested that the WAnT may not be an appropriate evaluation tool for anaerobic power assessment of water polo players, stressing the importance of sport-specific tests.

Biomechanical and physiological response to a contemporary soccer match-play simulation.

Abstract Page, RM, Marrin, K, Brogden, CM, and Greig, M. Biomechanical and physiological response to a contemporary soccer match-play simulation. J Strength Cond Res 29(10): 2860–2866, 2015—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 (T 0–15 = 206.26 ± 14.37 a.u. and T 45–60 = 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.”

The physical response to a simulated period of soccer-specific fixture congestion

Abstract Page, RM, Marrin, K, Brogden, CM, and Greig, M. Physical response to a simulated period of soccer-specific fixture congestion. J Strength Cond Res 33(4): 1075–1085, 2019—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 semiprofessional soccer players completed 3 trials of a treadmill-based match simulation, with 48 hours interspersing each trial. A repeated measures general linear model identified significantly (p = 0.02) lower knee flexor peak torque (PT) recorded at 300°·s−1 in the second (141.27 ± 28.51 N·m) and third trials (139.12 ± 26.23 N·m) when compared with the first trial (154.17 ± 35.25 N·m). Similarly, muscle soreness (MS) and PT data recorded at 60°·s−1 were significantly (p ⩽ 0.05) different in the third trial (MS = 42 ± 25 a.u; PT60 = 131.10 ± 35.38 N·m) when compared with the first trial (MS = 29 ± 29 a.u; PT60 = 145.61 ± 42.86 N·m). Significant (p = 0.003) differences were also observed for mean electromyography (EMGmean) of bicep femoris between the third trial (T0–15 = 126.36 ± 15.57 &mgr;V; T75–90 = 52.18 ± 17.19 &mgr;V) and corresponding time points in the first trial (T0–15 = 98.20 ± 23.49 &mgr;V; T75–90 = 99.97 ± 39.81 &mgr;V). Cumulative increases in perceived exertion, heart rate, oxygen consumption, blood lactate concentrations, EMGmean, and PlayerLoad (PL) were recorded across each trial. Muscle soreness and PT were also significantly different after trial. There were, however, no significant main effects or interactions for the salivary immunoglobulin A and the medial-lateral PL metrics. These data suggest a biomechanical and muscular emphasis with residual fatigue, with implications for injury risk and the development of recovery strategies.

Changes in knee extensor strength 8 and 24 hours after 2 types of endurance exercise [Annual conference of the british association of sport and exercise sciences]

We examined the lives of adults with cerebral palsy who had minimal involvement in physical activity (Judy, aged 60; Alana, aged 29), who were involved in physical activity (Amy, aged 25; Ben, aged, 30), or who had minimal involvement in physical activity and who then participated in physical activity (David, aged 27; Tim, aged, 24). After receiving ethical approval, a life-history research approach (Denzin, 1989: Interpretive biography. Newbury Park, CA: Sage) was used, with the participants’ stories being interpreted using primarily psychodynamic theory (Freud, Erikson, Adler, Basch) to gain insight into their meaning and experiences of physical activity. Judy and Alana had similar childhood experiences, which included: performing difficult, and sometimes painful, physiotherapy; wearing callipers to assist their walking; lacking competence at physical activity; and being socially isolated from their classmates. These aspects of their life histories seemed to contribute to their subsequent avoidance of physical activity and early onset of functional decline. Amy and Ben had negative experiences with physical activity as children (similar to Judy and Alana), but were involved in, and valued, physical activity as adults. Physical activity was a means of displaying competence, delaying further functional loss, and becoming socially connected. David and Tim lost the ability to walk in early adolescence. The minimal physical activity in which they engaged during their adult lives was directed towards trying to walk again. Walking seemed to be intimately connected with psychosocial growth. David’s weight-training programme seemed to provide him with another avenue for self-improvement towards his goal of attracting a life partner. Tim’s warm-water aerobic programme provided him with an opportunity to develop competence at swimming and at walking, and to enhance his self-esteem for these activities. Involvement in physical activity may be important for people with cerebral palsy in their endeavours to successfully face the various psychosocial challenges throughout life. Implications of this research include: parents and teachers of children with cerebral palsy should provide support for their involvement in physical activity; physiotherapists should try to reduce the pain and increase the perceived relevancy of the treatments they deliver to young people with cerebral palsy; and psychologists should be aware of some of the difficulties people with cerebral palsy face and how they may manifest in adults with the condition.A decreased kinematic variability was found in runners with patellofemoral pain compared with uninjured runners (Hamill et al., 1999: Clinical Biomechanics, 14, 297 – 308). Therefore, the aim of this study was to investigate the kinematic, kinetic, and EMG activity variability in runners with Achilles tendinopathy. Thirty-four uninjured runners (body mass 67.8±10.5 kg; height 1.71±0.09 m; age 37.0±9.2 years) and 25 runners diagnosed with Achilles tendinopathy (body mass 77.6±12.6 kg; height 1.78±0.07 m; age 41.8±9.7 years) were recruited. After receiving institutional ethics approval, the participants performed 10 trials at a self-selected running ...

Anthropometric and physiological characteristics of elite male dragon boat paddlers [Annual Conference of the British Association of Sport and Exercise Sciences]

Self-efficacy, an individual’s belief in his or her capabilities to perform a given behaviour (Bandura, 1997: Self-efficacy: The exercise of control. New York: Freeman), has been shown to have a significant influence on athletes’ performance. Given this, it is necessary to identify antecedents that may aid in enhancing positive self-efficacy perceptions among athletes. Previous research, albeit scarce, has been successful in demonstrating that the manner in which athletes ascribe causes to outcomes will impact upon their future efficacy expectations (e.g. Bond et al., 2001: International Journal of Sport Psychology, 31, 243–256; Gernigon & Delloye, 2003: The Sport Psychologist, 17, 55–76). However, the specific attributional dimensions implicated in the relationship has varied considerably. The aim of this study was to shed further light on the exact nature of the relationship between athletes’ causal thinking and their future efficacy perceptions. Specifically, it was hypothesized that following successful events, athletes who made more internal, stable and controllable attributions would show an increase in their self-efficacy perceptions post competition. In contrast, following unsuccessful performances, it was hypothesized that attributions to internal, stable and uncontrollable factors would accompany a decrease in athletes’ efficacy perceptions.Annual Conference of the British Association of Sport and