A 10-week plyometrics-based intervention was carried out with a county-level hurler during preseason preparation. The intervention resulted in a number of physiological changes specific to hurling performance. Most notably, it enabled the athlete to complete repeated sprints with less decrement in performance compared with baseline scores.
Michael J. Duncan, Mark Lyons and Joanne Hankey
This study examined the placebo effect of caffeine on number of repetitions (reps), rating of perceived exertion (RPE), blood pressure (BP), and peak heart rate (PHR) during resistance-training exercise with repetitions (reps) performed to volitional failure.
Following determination of 1-rep maximum in single-leg leg extension, 15 males performed reps to failure at 60% 1-RM in 3 conditions: control, perceived caffeine condition, and perceived placebo condition presented in a randomized order. Participants were informed they would ingest 250 mL of solution that contained either 3 mg·kg−1 caffeine or 3 mg·kg−1 placebo 1 h before each exercise trial. A deceptive protocol was employed and subjects consumed a placebo solution in both conditions. During each condition, total reps, RPE for the active muscle and overall body, and PHR were recorded.
Subjects completed 2 more reps when they perceived they had ingested caffeine. RPE was significantly (P = .04) lower in the perceived caffeine and control conditions and RPE for the active muscle was significantly higher across all conditions compared with RPE for the overall body. No substantial differences were evident in PHR across conditions.
Results of this study are similar to studies of actual caffeine ingestion. However, the perception of consuming a substance that purportedly enhances performance is sufficient enough to enable individuals to complete a greater number of reps to failure during short-term resistance exercise.
Neil D. Clarke and Michael J. Duncan
To investigate the effect of ingesting carbohydrate and caffeine solutions on measures that are central to success in badminton.
Twelve male badminton players performed a badminton serve-accuracy test, coincidence-anticipation timing (CAT), and a choice reaction-time sprint test 60 min before exercise. Participants then consumed 7 mL/kg body mass of either water (PLA), 6.4% carbohydrate solution (CHO), a solution containing a caffeine dose of 4 mg/kg, or 6.4% carbohydrate and 4 mg/kg caffeine (C+C). All solutions were flavored with orange-flavored concentrate. During the 33-min fatigue protocol, participants were provided with an additional 3 mL/kg body mass of solution, which was ingested before the end of the protocol. As soon as the 33-min fatigue protocol was completed, all measures were recorded again.
Short-serve accuracy was improved after the ingestion of CHO and C+C compared with PLA (P = .001, ηp 2 = .50). Long-serve accuracy was improved after the ingestion of C+C compared with PLA (P < .001, ηp 2 = .53). Absolute error in CAT demonstrated smaller deteriorations after the ingestion of C+C compared with PLA (P < .05; slow, ηp 2 = .41; fast, ηp 2 = .31). Choice reaction time improved in all trials with the exception of PLA, which demonstrated a reduction (P < .001, ηp 2 = .85), although C+C was faster than all trials (P < .001, ηp 2 = .76).
These findings suggest that the ingestion of a caffeinated carbohydrate solution before and during a badminton match can maintain serve accuracy, anticipation timing, and sprinting actions around the court.
Wesley O’Brien, Michael J. Duncan, Orlagh Farmer and Diarmuid Lester
Recent research has shown that post-primary Irish youth are insufficiently active and fail to reach a level of proficiency across basic fundamental movement skills. The purpose of the current research was to gather cross-sectional data on adolescent youth, differentiated by gender, specifically to inform the development of a targeted movement-oriented intervention. Data were collected on adolescents (N = 219; mean age : 14.45 ± 0.96 years), within two, mixed-gender schools. Data collection included actual and perceived movement measurements comprised of fundamental movement skills, the functional movement screen, perceived movement confidence, and perceived functional confidence. Overall, levels of actual mastery within fundamental and functional movement were low, with significant gender differences observed. Adolescent males scored higher in the overall fundamental movement skill domain (male mean score = 70.87 ± 7.05; female mean score = 65.53 ± 7.13), yet lower within the functional movement screen (male mean score = 13.58 ± 2.59), in comparison to their female counterparts (female mean score = 14.70 ± 2.16). There were high levels of perceived confidence reported within fundamental and functional movement scales. Future intervention strategies should combat the low levels of actual movement skill proficiency, while identifying the reasons for higher perceived movement confidence within adolescents.
Michael J. Duncan, Joanne Hankey and Alan M. Nevill
This study examined the efficacy of peak-power estimation equations in children using force platform data and determined whether allometric modeling offers a sounder alternative to estimating peak power in pediatric samples. Ninety one boys and girls aged 12–16 years performed 3 countermovement jumps (CMJ) on a force platform. Estimated peak power (PPest) was determined using the Harman et al., Sayers SJ, Sayers CMJ, and Canavan and Vescovi equations. All 4 equations were associated with actual peak power (r = 0.893−0.909, all p < .01). There were significant differences between PPest using the Harman et al., Sayers SJ, and Sayers CMJ equations (p < .05) and actual peak power (PPactual). ANCOVA also indicated sex and age effect for PPactual (p < .01). Following a random two-thirds to one-third split of participants, an additive linear model (p = .0001) predicted PPactual (adjusted R 2 = .866) from body mass and CMJ height in the two-thirds split (n = 60). An allometric model using CMJ height, body mass, and age was then developed with this sample, which predicted 88.8% of the variance in PPactual (p < .0001, adjusted R 2 = .888). The regression equations were cross-validated using the one-third split sample (n = 31), evidencing a significant positive relationship (r = .910, p = .001) and no significant difference (p = .151) between PPactual and PPest using this equation. The allometric and linear models determined from this study provide accurate models to estimate peak power in children.
Michael J. Duncan, Lorayne Woodfield, Yahya Al-Nakeeb and Alan M. Nevill
The purpose of this study was to compare physical activity levels between white and South Asian children in the UK. The data were obtained from 606, 11–14 year old schoolchildren (397 white; 209 Asian). Physical activity was assessed using the ‘four by one day’ recall questionnaire from which the time spent in moderate and vigorous physical activity was calculated. Boys were significantly more active than girls (p = .0001), and white children reported significantly greater physical activity than south Asian children (p = .001). Mean ± SD of time spent in moderate and vigorous activity was 90.2 ± 65.4 mins and 68.2 ± 49.3 mins for white and south Asian children and 103.5 ± 63.4 mins and 65.6 ± 53.5 mins for boys and girls respectively. These findings indicate that south Asian children are significantly less active than their white peers and there may be a need for specific interventions to target South Asian children particularly.
Nadia Cristina Valentini, Glauber Carvalho Nobre, Mariele Santayana de Souza and Michael J. Duncan
Background: Higher levels of actual and perceived motor competence are purported to lead to participation in physical activity (PA). Whereas considerable work has been published regarding motor and perceived competence and body mass index (BMI), much less is known about the association of these variables considering PA and engagement in physical education settings—the focus of the present study. Method: In 600 children (aged 3–10 y), PA during physical education lessons, locomotor skills, object control skills, perceived competence, and BMI (study 1) were assessed. In a subsample of 149 children, PA, engagement, and health-related fitness were assessed (study 2). Results: Structural equation model showed that in study 1, locomotor skills were the strongest variable in the early years, and object control skills were the strongest later, in explained PA. The regression analysis, in study 2, showed that BMI, object control skills, and engagement were significantly associated with PA and that appropriate motor engagement was the best predictor of PA. Conclusion: The authors extended previous research by providing evidence that motor competence varies across childhood in explaining participation in PA, and appropriate motor engagement plays a critical role in being active during lessons and was the strongest predictor of PA. BMI and self-perception were not significant in the models.
Emma L. J. Eyre, Jason Tallis, Susie Wilson, Lee Wilde, Liam Akhurst, Rildo Wanderleys and Michael J. Duncan
Background: The ability to objectively assess physical activity and inactivity in free living individuals is important in understanding activity patterns and the dose response relationship with health. Currently, a large number of research tools exist, but little evidence has examined the validity/utility of the Research Tracker 6 (RT6) monitor. Questions remain in regard to the best placements, positions, and cut-points in young adults to determine activity intensity across a range of activities. This study sought to address this gap in young adults. The study aims were 1) to examine criterion validity of RT6 in comparison to breath-by-breath gas analysis; 2) convergent validity of RT6 in comparison to ActiGraph and GENEActiv; 3) development of RT6 tri-axial vector magnitude cut-points to classify physical activity at different intensities (i.e., for sedentary, moderate, and vigorous); 4) to compare the generated cut-points of the RT6 in comparison to other tools. Methods: Following ethics approval and informed consent, 31 young adults (age = 22±3 years: BMI = 23±3 kg/m2) undertook five modes of physical activity/sedentary behaviors while wearing three different accelerometers at hip and wrist locations (ActiGraph GT9X Link, GENEActiv, RT6). Expired gas was sampled during the five activities (MetaMax 3B). Correlational analysis assessed the relationship between accelerometer devices and METs/VO2. Receiver Operating Characteristic Curves analysis were used to calculate area under the curve and define cut-points for physical activity intensities. Results: The RT6 demonstrated criterion and convergent validity (r = 0.662–0.966, P < .05). RT6 generally performed good to excellent across activity intensities and monitor position (sedentary [AUC = 0.862–0.911], moderate [AUC = 0.849–0.830], vigorous [AUC = 0.872–0.877]) for non-dominant and dominant position, respectively. Cut-points were derived across activity intensities for non-dominant- and dominant-worn RT6 devices. Comparison of the RT6 derived cut-points identified appropriate agreement with comparative tools but yields the strongest agreement with the ActiGraph monitor at the hip location during sedentary, light, and moderate activity. Conclusion: The RT6 performed similar to the ActiGraph and GENEActiv and is capable of classifying the intensity of physical activity in young adults. As such this may offer a more useable tool for understanding current physical activity levels and in intervention studies to monitor and track changes without the excessive need for downloading and making complex analysis, especially given the option to view energy expenditure data while wearing it. The RT6 should be placed on the dominant hip when determining activities that are sedentary, moderate, or vigorous intensity.
William J. Kraemer, Ana L. Gómez, Nicholas A. Ratamess, Jay R. Hoffman, Jeff S. Volek, Martyn R. Rubin, Timothy P. Scheett, Michael R. McGuigan, Duncan French, Jaci L. VanHeest, Robbin B. Wickham, Brandon Doan, Scott A. Mazzetti, Robert U. Newton and Carl M. Maresh
To determine the effects of Vicoprofen®, ibuprofen, and placebo on anaerobic performance and pain relief after resistance-exercise-induced muscle damage.
Randomized, controlled clinical study.
University human-performance/sports-medicine laboratory.
36 healthy men.
Methods and Measures:
After baseline testing (72 h), participants performed an eccentric-exercise protocol. Each was evaluated for pain 24 h later and randomly assigned to a Vicoprofen (VIC), ibuprofen (IBU), or placebo (P) group. Postexercise testing was performed every 24 h for 4 d.
Significantly greater muscle force, power, and total work were observed in VIC than in P (P < .05) for most time points and for IBU at 48 h.
Anaerobic performance is enhanced with VIC, especially within the first 24 h after significant muscle-tissue damage. The greater performances observed at 48 h might be a result of less damage at this time point with VIC treatment.