Increasing meal frequency in combination with exercise mitigates postprandial triacylglycerol

Background: This study examined how manipulating meal frequency, with and without exercise, affects postprandial triacylglycerol (TAG). Methods: Fourteen sedentary men completed four 2-day trials in a non-counterbalanced random crossover order: (i) consumption of one large high fat milkshake without exercise (1-CON); (ii) consumption of two smaller high fat milkshakes without exercise (2-CON); (iii) consumption of one large high fat milkshake with exercise (1-EX); and (iv) consumption of two small high fat milkshakes with exercise (2-EX) – total energy intake was standardized across trials. On Day 1, participants rested (1-CON and 2- CON) or walked briskly for 60 minutes (1-EX and 2-EX). On Day 2, participants consumed either a single large high-fat milkshake (75% fat) (1-CON and 1-EX) for breakfast or two smaller iso-energetic milkshakes (2-CON and 2-EX) for breakfast and lunch. Plasma TAG were measured fasting and for 7 hours after breakfast. Results: Peak incremental TAG was 30% lower on 2-EX than 1-CON (P = .041; d = 0.38). Postprandial TAG increased more rapidly in the first 4 hours in 1-CON than other trials, but at 6 hours TAG was exaggerated in 2-CON compared with 1-CON. Conclusions: Increasing meal frequency after exercise, without altering overall fat intake, attenuates postprandial TAG

Optimising classification of proximal arm strength impairment in wheelchair rugby: A proof of concept study

This study examined the relationship between proximal arm strength and mobility performance in wheelchair rugby (WR) athletes and examined whether a valid structure for classifying proximal arm strength impairment could be determined. Fifty-seven trained WR athletes with strength impaired arms and no trunk function performed six upper body isometric strength tests and three 10 m sprints in their rugby wheelchair. All strength measures correlated with 2 m and 10 m sprint times (r 65 120.43; p 64\ua00.0005) and were entered into k-means cluster analyses with 4-clusters (to mirror the current International Wheelchair Rugby Federation [IWRF] system) and 3-clusters. The 3-cluster structure provided a more valid structure than both the 4-cluster and existing IWRF system, as evidenced by clearer differences in strength (Effect sizes [ES] 65 1.0) and performance (ES 65 1.1) between adjacent clusters and stronger mean silhouette coefficient (0.64). Subsequently, the 3-cluster structure for classifying proximal arm strength impairment would result in less overlap between athletes from adjacent classes and reduce the likelihood of athletes being disadvantaged due to their impairment. This study demonstrated that the current battery of isometric strength tests and cluster analyses could facilitate the evidence-based development of classifying proximal arm strength impairment in WR

Force–velocity profiling of elite wheelchair rugby players by manipulating rolling resistance over multiple wheelchair sprints

This study investigated the effect of increased rolling resistance on wheelchair sprint performance and the concomitant force-velocity characteristics. Thirteen wheelchair rugby (WCR) athletes completed five 15 s wheelchair sprints in their own rugby wheelchair on an instrumented dual-roller wheelchair ergometer. The first sprint was performed against a close to overground resistance and in each of the following sprints, the resistance increased with 80% of that resistance. A repeated-measures ANOVA examined differences between sprints. Subsequently, linear regression analyses examined the individual force-velocity relations and then, individual parabolic power output curves were modeled. Increased rolling resistance led to significantly lower velocities (-36%), higher propulsion forces (+150%) and higher power outputs (+83%). These differences were accompanied by a lower push frequency, higher push time, yet a constant recovery time and contact angle. The modeled linear regressions (R 2  = 0.71 ± 0.10) between force and velocity differed a lot in slope and intercept among individual athletes. The peak of the power output parabola (i.e., the optimal velocity) occurred on average at 3.1 ± 0.6 ms -1 . These individual force-velocity profiles can be used for training recommendations or technological changes to better exploit power generation capabilities of the WCR athletes' musculoskeletal system. </p

The influence of crank length and cadence on mechanical efficiency in hand cycling

The purpose of this study was to determine the effect of crank length and cadence on mechanical efficiency in hand cycling. Eight wheelchair dependent, high performance athletes completed four 4-min submaximal exercise bouts at a constant power output of 90 W over the different experimental conditions (crank length, pedal rate) using a sports hand bike (Draft, Godmanchester, UK). Two different crank lengths (180 and 220 mm) were tested at two different cadences (70 and 85 rev min−1) using the synchronous mode of cranking. Physiological measures of oxygen uptake VO2, minute ventilation, blood lactate (B[La]), heart rate (HR), rate of perceived exertion (RPE) were recorded, gross (GE) and net (NE) efficiency were calculated. A two-way ANOVA with repeated measures was applied to determine the effects of crank length, cadence and their interaction on these physiological measures. Both GE and NE were significantly higher and VO2 significantly lower for the 180 mm crank (P 0.05). Likewise, no interactions between crank length and pedal rate were found. There was however, a trend observed with HR and B[La] often lower with the 180 mm crank, indicating lower physiological stress. The RPE data supported this finding, with a tendency for lower ratings with the 180 mm crank (9 ± 2 vs. 10 ± 3). The short crank length when used at 85 rev min−1 was found to be the most efficient (GE 21.4 ± 3.1%). In conclusion, crank length has a significant effect on ME in hand cycling. A shorter crank length of 180 mm was found to be more efficient than the 220 mm, regardless of pedal rate during hand cycling