T. McGuckin

Influence of exercise intensity on systemic oxidative stress and antioxidant capacity.

The aim of the current study was to examine the influence of exercise intensity on systemic oxidative stress (OS) and endogenous antioxidant capacity. Non‐smoking, sedentary healthy adult males (n = 14) participated in two exercise sessions using an electronically braked cycle ergometer. The first session consisted of a graded exercise test to determine maximal power output and oxygen consumption (VO2max). One week later, participants undertook 5‐min cycling bouts at 40%, 55%, 70%, 85% and 100% of VO2max, with passive 12‐min rest between stages. Measures of systemic OS reactive oxygen metabolites (dROM), biological antioxidant potential (BAP), heart rate (HR), VO2, blood lactate and rating of perceived exertion were assessed at rest and immediately following each exercise stage. Significant (P<0·05) differences between exercise bouts were examined via repeated measures ANOVA and post hoc pairwise comparisons with Bonferroni correction. Increasing exercise intensity significantly augmented HR (P<0·001), VO2 (P<0·001), blood lactate (P<0·001) and perceived exertion (P<0·001) with no significant effect on dROM levels compared with resting values. In contrast, increasing exercise intensity resulted in significantly (P<0·01) greater BAP at 70% (2427 ± 106), 85% (2625 ± 121) and 100% (2651 ± 92) of VO2max compared with resting levels (2105 ± 57 μmol Fe2+/L). The current results indicate that brief, moderate‐to‐high‐intensity exercise significantly elevates endogenous antioxidant defences, possibly to counteract increased levels of exercise‐induced reactive oxygen species. Regular moderate‐to‐high‐intensity exercise may protect against chronic OS associated diseases via activation, and subsequent upregulation of the endogenous antioxidant defence system.

The effects of air travel on performance measures of elite Australian rugby league players

Abstract The current study explored the effects of short haul air travel within the same country on elite Australian rugby league (RL) players (n=12) during two away and two home games of elite competition. Physiological tests of handgrip strength and leg power were assessed along with psychological tests and perceptions of leg soreness and tiredness on the day before the game (Time 1 and Time 2) and on game day (Time 3). Game statistics of tackles and metres gained were assessed for the games analysed. Significant differences were found for daily analyses of life demands for athletes (DALDA) worse than normal responses at Time 2 (2.50±3.23 vs. 3.50±3.93; P=0.04), Karolinska Sleepiness Scale (KSS) at Time 2 (2.88±1.51 vs. 3.71±1.37; P=0.011) and leg tiredness at Time 3 (3.38±1.66 vs. 2.35±1.70; P=0.004) between home and away games. The analysis of game statistics identified that more metres were gained during home games (83.6±49.1 vs. 63.0±30.1; P=0.02) and more tackles made while playing away (18.4±9.2 vs. 14.3±6.7; P=0.016). The results suggest that short haul air travel without crossing time zones results in symptoms of travel fatigue but does not appear to negatively impact on elite RL players ability to perform strength and power tasks. Different game tactics (attacking vs. defensive) occurred between home and away games however, it is unclear whether travel fatigue or a home advantage (HA) is associated with this finding.

Planning for sedentary behaviour interventions: office workers' survey and focus group responses

Aims: As sedentary behaviour is becoming more prominent in office-based work environments, this study aimed to explore office workers’ perceptions of sedentary behaviour, explore potential behavioural strategies to reduce sedentary behaviour in the workplace and identify barriers which may hamper behaviour change. Methods: A total of 140 office workers were recruited and surveyed from the same workplace. The survey included questions regarding perceptions of the relationship between sitting time and health. Following the survey, 12 employees also participated in focus groups to identify potential sedentary behaviour intervention strategies and barriers. The responses from the survey and focus groups were thematically analysed. Results: In total, 88% of all participants surveyed agreed that there was a relationship between sitting time and their health. The most prominent theme identified was musculoskeletal complaints followed by general health and weight gain or obesity. The focus groups identified that interventions targeting reducing sitting time should include education, supportive and knowledgeable managers, and a variety of behaviour change strategies to address individual preferences and barriers. Conclusion: Multiple behavioural strategies were identified, which appear to be appropriate for sedentary behaviour change.

The use and evaluation of a theory-informed, multi-component intervention to reduce sedentary behaviour in the workplace

Abstract Occupational sedentary behaviour is a growing health concern which accounts for almost half of overall sedentary behaviour. Multi-component interventions are effective for reducing occupational sedentary behaviour. The aim of the study was to evaluate the effectiveness of a theory-informed, personalised intervention for the reduction of occupational sedentary behaviour of office workers. Full-time office-based workers were asked to complete an online survey to explore their perception of sedentary behaviour. Following this, pre-intervention activity patterns were collected for 5 days via an ActivPAL and a self-report workbook. The participants met with the investigator to discuss the key themes identified from the online survey, individual ActivPAL and self-report data. Participants set goals for the 6-week intervention, signed a commitment contract with stage of change and self-efficacy explored. During the final intervention week, participants wore an ActivPAL and were invited to participate in a follow-up interview. Twenty-seven office-based workers reduced occupational sitting time by an average of 45.2 ± 60.7 min per workday. Self-efficacy increased post intervention (pre: 69 ± 21%; post: 82 ± 16%). The follow-up interviews indicated that the intervention increased awareness of occupational sedentary behaviour and provided insight into the key behaviour change strategies utilised in the intervention.

Six-month follow-up of a theory-informed, multi-component intervention to reduce sedentary behaviour in the workplace

Abstract There is limited evidence exploring the long-term effectiveness of sedentary behaviour interventions. This study aimed to explore participant experiences six months post-intervention to evaluate the long-term effectiveness of a low-cost, theory-informed, multi-component, individually tailored, six-week intervention for the reduction of occupational sedentary behaviour. Twenty-five participants who completed a sedentary behaviour intervention participated in a six-month follow-up. Participants wore an activity monitoring device and participated in a semi-structured interview. Interview transcripts were thematically analysed. The pre- and post-intervention quantitative data were analysed via paired samples t-tests. Occupational sitting time was reduced by an average of 40.6 ± 76.1 min/work day at six months as compared to pre-intervention. Twenty-three participants indicated that they had continued with their occupational sedentary behaviour change with various stages of change identified. Self-efficacy towards goal achievement remained high at the six-month follow-up. The most prominent goal identified by the participants to reduce occupational sedentary behaviour was walking. Barriers included attending seated meetings, perceived workloads or work tasks and work environments. Suggested strategies to overcome barriers included changing the work environment, providing prompts and receiving support from management. The current study provides insight into the long-term adherence to an occupational sedentary behaviour intervention.

How many consecutive days of pedometer monitoring is required to estimate weekly physical activity levels of young healthy adults

Introduction: Pedometers are an inexpensive and convenient way to measure physical activity, Several studies have suggested that 3-5 days of pedometer monitoring are required for accurate and reliable estimates of daily physical activity levels in mature adults, However, the minimum number of days of monitoring needed to estimate total physical activity over a week for young adults is unknown. The aim of the current study was to determine the number of consecutive days needed to estimate weekly pedometer-based physical activity levels for young healthy adults. Methods: Eighty-two (31 males, 51 females) healthy adults volunteered for this study (age 20,4±4,1 yrs). All participants provided informed written consent prior to participation with all procedures conducted in accordance with approval of the local university Human Ethics Sub-Committee. Participants wore a Yamax Digi-Walker SW-700 pedometer (yamax, Japan) on their waist for seven consecutive days during wakeful hours (except water based activities). At the end of each day, participants recorded the number of steps taken, Differences in daily physical activity were determined via 1-way ANOVA while estimates of weekly physical activity were assessed via linear stepwise regression. Results: Significantly less physical activity was undertaken on Sunday compared to Monday and Thursday (p<0,05), Stepwise regression analysis identified that one day (Wednesday) accounted for 48.1 % of the model variance with two (Wednesday-Thursday), three (Wednesday-Friday), four (Saturday-Tuesday) and five (Wednesday-Sunday) consecutive days accounting for 64.9%, 79.2%, 85.5% and 93.5% of the model variance. Discussion: The results of the current study suggest that five consecutive days (Wednesday-Sunday) will accurately estimate total weekly physical activity level based on pedometer measures in young adults.