Search Results

You are looking at 1 - 5 of 5 items for

  • Author: Vincent G. Kelly x
Clear All Modify Search
Restricted access

Brandon M. Wellington, Michael D. Leveritt and Vincent G. Kelly

Context:

Repeat-high-intensity efforts (RHIEs) have recently been shown to occur at critical periods of rugby league matches.

Purpose:

To examine the effect that caffeine has on RHIE performance in rugby league players.

Methods:

Using a double-blind, placebo-controlled, crossover design, 11 semiprofessional rugby league players (age 19.0 ± 0.5 y, body mass 87.4 ± 12.9 kg, height 178.9 ± 2.6 cm) completed 2 experimental trials that involved completing an RHIE test after either caffeine (300 mg caffeine) or placebo (vitamin H) ingestion. Each trial consisted of 3 sets of 20-m sprints interspersed with bouts of tackling. During the RHIE test, 20-m-sprint time, heart rate (HR), rating of perceived exertion (RPE), and blood lactate were measured.

Results:

Total time to complete the nine 20-m sprints during the caffeine condition was 1.0% faster (28.46 ± 1.4 s) than during the placebo condition (28.77 ± 1.7 s) (ES = 0.18, 90%CI –0.7 to 0.1 s). This resulted in a very likely chance of caffeine being of benefit to RHIE performance (99% likely to be beneficial). These improvements were more pronounced in the early stages of the test, with a 1.3%, 1.0%, and 0.9% improvement in sprint performance during sets 1, 2, and 3 respectively. There was no significant difference in RPE across the 3 sets (P = .47, 0.48, 1.00) or mean HR (P = .36), maximal HR (P = .74), or blood lactate (P = .50) between treatment conditions.

Conclusions:

Preexercise ingestion of 300 mg caffeine produced practically meaningful improvements in RHIE performance in rugby league players.

Restricted access

Suzanna Russell, Angus G. Evans, David G. Jenkins and Vincent G. Kelly

Purpose: To determine the efficacy of 20 minutes of external counterpulsation (ECP) on subsequent 1.2-km shuttle run test (1.2SRT) performance and perceived recovery following fatiguing high-intensity exercise. Methods: After familiarization, 13 recreationally active males (21.4 [1.9] y) participated in 2 experimental trials in a randomized crossover design. At 8:00 AM, participants completed a 1.2SRT, followed by an individualized high-intensity exercise bout and 20 minutes of ECP or supine passive rest (control). At 2:00 PM a second 1.2SRT was completed. Completion time for 1.2SRT (measured in seconds), heart rate, and Borg rating of perceived exertion were compared across conditions. Total quality of recovery and 100-mm visual analogue scale of perceived benefit of recovery were assessed at multiple time points. Results: A significantly smaller decline in PM 1.2SRT completion time compared with AM (baseline) was found for ECP compared with control (P = .008; moderate, very likely beneficial effect size of −0.77 [−1.53 to 0.05]). Total quality of recovery was significantly higher for ECP than control (P < .001), and perceived benefit of recovery was higher following ECP (P < .001, very large, most likely beneficial effect size of 2.08 [1.22 to 2.81]). Conclusions: Twenty minutes of ECP was found to be an effective recovery modality for within-day, between-bouts exercise, positively influencing subsequent 1.2SRT performance and enhancing perceptual recovery. ECP may be applied as a viable alternative to optimize and accelerate the recovery process, particularly in the event of congested training or competition demands.

Restricted access

Lachlan P. James, Emma M. Beckman, Vincent G. Kelly and G. Gregory Haff

Purpose:

To determine whether the maximal strength, impulse, and power characteristics of competitive mixed-martial-arts (MMA) athletes differ according to competition level.

Methods:

Twenty-nine male semiprofessional and amateur MMA competitors were stratified into either higher-level (HL) or lower-level (LL) performers on the basis of competition grade and success. The 1-repetition-maximum (1RM) squat was used to assess lower-body dynamic strength, and a spectrum of impulse, power, force, and velocity variables were evaluated during an incremental-load jump squat. In addition, participants performed an isometric midthigh pull (IMTP) and 1RM bench press to determine whole-body isometric force and upper-body dynamic strength capabilities, respectively. All force and power variables were expressed relative to body mass (BM).

Results:

The HL competitors produced significantly superior values across a multitude of measures. These included 1RM squat strength (1.84 ± 0.23 vs 1.56 ± 0.24 kg BM; P = .003), in addition to performance in the incremental-load jump squat that revealed greater peak power (P = .005–.002), force (P = .002–.004), and velocity (P = .002–.03) at each load. Higher measures of impulse (P = .01–.04) were noted in a number of conditions. Average power (P = .002–.02) and velocity (P = .01–.04) at all loads in addition to a series of rate-dependent measures were also superior in the HL group (P = .005–.02). The HL competitors’ 1RM bench-press values approached significantly greater levels (P = .056) than the LL group’s, but IMTP performance did not differ between groups.

Conclusions:

Maximal lower-body neuromuscular capabilities are key attributes distinguishing HL from LL MMA competitors. This information can be used to inform evidenced-based training and performance-monitoring practices.

Restricted access

Marni J. Simpson, David G. Jenkins, Aaron T. Scanlan and Vincent G. Kelly

Purpose: To examine relationships between external- and internal-workload variables in an elite female netball team, with consideration of positional differences. Methods: Nine elite female netball athletes had their weekly workloads monitored across their preseason and competition phases of a season. Internal workload was determined using summated heart-rate (HR) zones and session ratings of perceived exertion (sRPE), whereas external workload was determined using inertial movement units and included absolute PlayerLoad (PL), relative PL (PL per minute), accelerations (ACCEL), decelerations (DECEL), jumps, changes of direction (COD), high-intensity events, medium-intensity events, low-intensity events, PL in the forward direction, PL in the sideways direction, and PL in the vertical direction. Relationships between external- and internal-workload variables in the team and relative to playing position were examined. Results: Across the team, the strongest external workloads that correlated with summated HR zones were PL (r = .65), COD (r = .64), ACCEL (r = .61), and DECEL (r = .61). The strongest external workloads that correlated with sRPE were COD (r = .79), followed by jumps (r = .76), ACCEL (r = .75), and DECEL (r = .75). For all positions, except-goal shooter, the strongest correlation was between PL and sRPE (r = .88–.94). In the goal-shooter position, the strongest correlation was between summated HR zones and DECEL (r = .89). Conclusions: The inertial movement unit-derived external-workload variables are strongly related to common internal-workload variables. In particular, COD and sRPE appear to provide a good monitoring combination of external and internal training loads for elite netball players.

Restricted access

Llion A. Roberts, Johnpaul Caia, Lachlan P. James, Tannath J. Scott and Vincent G. Kelly

Purpose: External counterpulsation (ECP) has previously been used to treat cardiac patients via compression of the lower extremities during diastole to increase venous return and coronary perfusion. However, the effects of ECP on exercise performance and markers of recovery in elite athletes are largely unknown. Methods: On 2 separate occasions, 48 h apart, 7 elite National Rugby League players performed an identical 60-min field-based conditioning session followed by a 30-min period of either regular ECP treatment or placebo. Power measures during repeated cycle bouts and countermovement jump height and contraction time derivatives were measured at rest and 5 h postexercise. Saliva samples and venous blood samples were taken at rest, postexercise, and 5 h postexercise to assess stress, inflammation, and muscle damage. Results: After ECP treatment, cycling peak power output (P = .028; 11%) and accumulated peak power (P = .027; 14%) increased compared with the placebo condition. Postexercise plasma interleukin 1 receptor antagonist only increased after ECP (P = .024; 84%), and concentrations of plasma interleukin 1 receptor antagonist tended to be higher (P = .093; 76%) 5 h postexercise. Furthermore, testosterone-to-cortisol ratio was increased above baseline and placebo 5 h postexercise (P = .017–.029; 24–77%). The ratio of postexercise salivary α-amylase to immunoglobulin A decreased after treatment (P = .013; 50%) compared with the placebo control. Conclusions: Exercise performance and hormonal indicators of stress were improved and inflammation markers were reduced following acute ECP.