Dale I. Lovell

Biochemical and endocrine responses to impact and collision during elite rugby league match play

McLellan, CP, Lovell, DI, and Gass, GC. Biochemical and endocrine responses to impact and collision during elite rugby league match play. J Strength Cond Res 25(6): 1553-1562, 2011—The purpose of this study was to investigate the relationship between the prematch and short-term postmatch biochemical and endocrine responses to the intensity, number, and distribution of impacts associated with collisions during elite Rugby League match play. Seventeen elite male Rugby League players each provided blood and saliva samples 24 hours prematch, 30 minutes prematch, 30 minutes postmatch, and then at 24-hour intervals for a period of 5 days postmatch to determine plasma creatine kinase concentration ([CK]) and salivary cortisol concentration ([sCort]). The intensity, number, and distribution of impact forces experienced by players during match play were recorded using portable global positioning systems (GPSs). The change in the dependent variables at each sample collection time was compared to 24 hours prematch and 30-minute prematch measures. The [CK] and [sCort] increased significantly (p < 0.05) during match play. Significant correlations (p < 0.05) were observed between the number of hit-ups and peak [CK] 24 hours postmatch, 48 hours postmatch, and 72 hours postmatch (p < 0.05). The number of impacts recorded in zone 5 (8.1-10.0G) and zone 6 (>10.1G) during match play was significantly correlated (p < 0.05) to [CK] 30 minutes postmatch, 24 hours post, 48 hours post, and 72 hours postmatch. The GPS was able to provide data on the intensity, number, and distribution of impacts resulting from collisions during match play. Elite Rugby League match play resulted in significant skeletal muscle damage and was highly dependent on the number of heavy collisions >8.1G. [CK] remained elevated 120 hours postmatch identifying that at least 5 days modified activity is required to achieve full recovery after elite Rugby League match play.

Markers of Postmatch Fatigue in Professional Rugby League Players

McLellan, CP, Lovell, DI, and Gass, GC. Markers of postmatch fatigue in professional rugby league players. J Strength Cond Res 25(4): 1030-1039, 2011-The aim of the present study was to identify neuromuscular, biochemical, and endocrine markers of fatigue after Rugby League match play. Seventeen elite Rugby League players were monitored for a single match. Peak rate of force development (PRFD), peak power (PP), and peak force (PF) were measured during a countermovement jump (CMJ) on a force plate pre and postmatch play. Saliva and blood samples were collected 24 hours prematch, 30 minutes prematch, 30 minutes postmatch, and then at 24-hour intervals for a period of 120 hours to determine plasma creatine kinase concentration ([CK]) and salivary cortisol concentration ([sCort]). There were significant (p < 0.05) decreases in PRFD and PP up to 24 hours postmatch with PF significantly (p < 0.05) decreased immediately postmatch. The [sCort] significantly (p < 0.05) increased from 24 hours prematch to 30 minutes prematch and up to 24 hours postmatch compared with 24 hours prematch. Plasma [CK] significantly (p < 0.05) increased 30 minutes postmatch with a peak occurring 24 hours postmatch and remained elevated above 24 hours prematch for at least 120 hours postmatch. There were significant (p < 0.05) correlations between the increase in [CK] and reduction in PRFD 30 minutes postmatch and 24 hours postmatch. The [sCort] was significantly (p < 0.05) correlated with the reduction in PF 30 minutes postmatch. Results demonstrate that neuromuscular function is compromised for up to 48 hours after match play. Elevated [CK] despite 120-hour recovery indicate that damage to muscle tissue after Rugby League match play may persist for at least 5 days postmatch. Despite the prolonged presence of elevated [CK] postmatch, strength training 48 hours postmatch may have resulted in a compensatory increase in PRFD supporting the inclusion of strength training during the short-term postmatch recovery period.

Creatine Kinase and Endocrine Responses of Elite Players Pre, During, and Post Rugby League Match Play

McLellan, CP, Lovell, DI, and Gass, GC. Creatine kinase and endocrine responses of elite players pre, during, and post rugby league match play. J Strength Cond Res 24(11): 2908-2919, 2010-The purpose of the present study was to (a) examine player-movement patterns to determine total distance covered during competitive Rugby League match play using global positioning systems (GPSs) and (b) examine pre, during, and postmatch creatine kinase (CK) and endocrine responses to competitive Rugby League match play. Seventeen elite rugby league players were monitored for a single game. Player movement patterns were recorded using portable GPS units (SPI-Pro, GPSports, Canberra, Australia). Saliva and blood samples were collected 24 hours prematch, 30 minutes prematch, 30 minutes postmatch, and then at 24-hour intervals for a period of 5 days postmatch to determine plasma CK and salivary testosterone, cortisol, and testosterone:cortisol ratio (T:C). The change in the dependent variables at each sample collection time was compared to 24-hour prematch measures. Backs and forwards traveled distances 5,747 ± 1,095 and 4,774 ± 1,186 m, respectively, throughout the match. Cortisol and CK increased significantly (p < 0.05) from 30 minutes prematch to 30 minutes postmatch. Creatine kinase increased significantly (p < 0.05) postmatch, with peak CK concentration measured 24 hours postmatch (889.25 ± 238.27 U·L−1). Cortisol displayed a clear pattern of response with significant (p < 0.05) elevations up to 24 hours postmatch, compared with 24 hours prematch. The GPS was able to successfully provide data on player-movement patterns during competitive rugby league match play. The CK and endocrine profile identified acute muscle damage and a catabolic state associated with Rugby League match play. A return to normal T:C within 48 hours postmatch indicates that a minimum period of 48 hours is required for endocrine homeostasis postcompetition. Creatine kinase remained elevated despite 120 hours of recovery postmatch identifying that a prolonged period of at least 5 days modified activity is required to achieve full recovery after muscle damage during competitive Rugby League match play.

Neuromuscular Responses to Impact and Collision During Elite Rugby League Match Play

Abstract McLellan, CP and Lovell, DI. Neuromuscular responses to impact and collision during elite rugby league match play. J Strength Cond Res 26(5): 1431–1440, 2012—The purpose of this study was to investigate the relationship between the prematch and short-term postmatch neuromuscular responses to the intensity, number, and distribution of impacts associated with collisions during elite Rugby League match play. Twenty-two elite male Rugby League players were monitored during 8 regular season competition matches using portable global positioning system (GPS) technology. The intensity, number, and distribution of impact forces experienced by players during match play were recorded using integrated accelerometry. Peak rate of force development (PRFD), peak power (PP), and peak force (PF) were measured during a countermovement jump on a force plate 24 hours prematch, 30 minutes prematch, 30 minutes postmatch and then at 24-hour intervals for a period of 5 days postmatch. The change in the dependent variables at each sample collection time was compared with that at 24 hours prematch and 30-minute prematch measures. There were significant (p < 0.05) decreases in PRFD and PP up to 24 hours postmatch with PF significantly (p < 0.05) being decreased 30 minutes postmatch. Significant (p < 0.05) correlations were found between the total number of impacts and PRFD and PP 30 minutes postmatch. Impact zones 4 (7.1–8.0 G), 5 (>8.1–10.0 G), and 6 (>10.1 G) were significantly (p < 0.05) correlated to PRFD and PP 30 minutes postmatch with the number of zone 5 and 6 impacts significantly (p < 0.05) correlated to PRFD and PP 24 hours postmatch. Elite Rugby League match play resulted in significant neuromuscular fatigue and was highly dependent on the number of heavy collisions >7.1G. Results demonstrate that neuromuscular function is compromised for up to 48 hours postmatch indicating that at least 2 days of modified activity is required to achieve full neuromuscular recovery after elite Rugby League match play. Position-specific demands on energy systems and the influence of repeated blunt force trauma during collisions during elite Rugby League match play should be considered when planning postmatch recovery protocols and training activities to optimize subsequent performance.

Performance analysis of professional, semiprofessional, and junior elite rugby league match-play using global positioning systems

Abstract McLellan, CP and Lovell, DI. Performance analysis of professional, semiprofessional, and junior elite rugby league match-play using global positioning systems. J Strength Cond Res 27(12): 3266–3274, 2013—The aim of the present study was to examine the positional differences in physical performance measures of professional, semiprofessional, and junior elite rugby league match-play using portable Global Positioning Systems (GPSs). Twelve professional, 12 semiprofessional, and 18 junior elite male rugby league players were monitored during 5 regular-season competition matches using portable GPS software. The mean total distance traveled during professional (8,371 ± 897 m) and semiprofessional (7,277 ± 734 m) match-play was significantly (p < 0.05) greater than that traveled during elite junior (4,646 ± 978 m) match-play. Position-specific total distance traveled and distance traveled per minute of playing time were significantly (p < 0.05) less for junior elite backs (5,768 ± 765 m; 74 ± 11 m·min−1) and forwards (4,774 ± 564 m; 82 ± 5 m·min−1) in comparison to those in professional (backs: 8,158 ± 673 m; 101 ± 8 m·min−1 and forwards: 8,442 ± 812 m; 98 ± 12 m·min−1) and semiprofessional (backs: 7,505 ± 765 m; 94 ± 8 m·min−1 and forwards: 6,701 ± 678 m; 89 ± 8 m·min−1) match-play. Maximum running speed, maximum sprints, and total sprint distance traveled by professional players were all significantly (p < 0.05) greater than those traveled by junior elite players but not semiprofessional players during match-play. Professional backs and forwards performed significantly (p < 0.05) more maximum sprints and traveled greater total distance during match-play in comparison to semiprofessional and junior elite players. The present findings demonstrate minimal differences in the physical performance measures of professional and semiprofessional rugby league match-play. The position-specific performance characteristics of junior elite match-play indicate that current junior elite player-development pathways may not provide adequate preparation for players transitioning into professional competition.

Strength training improves submaximum cardiovascular performance in older men

ABSTRACT Purpose: To determine if 16 weeks of strength training can improve the cardiovascular function of older men during sub‐maximum aerobic exercise. Methods: Twenty four men aged 70‐80 yr were randomly assigned to a strength training (ST; n = 12) and control group (C; n = 12). Training consisted of 3 sets of 6 ‐ 10 repetitions at 70% to 90% of 1RM, 3 times per week, on an incline squat machine for 16 weeks, followed by 4 weeks detraining. Leg strength and maximum oxygen consumption (VO2 max) were assessed every 4 weeks of the 20‐week study. Cardiovascular function was assessed during submaximum cycle exercise at 40 Watts, 50% and 70% of VO2 max before training, after 16 weeks training, and after 4 weeks detraining. Results: At 40 Watts, heart rate (HR), systolic blood pressure, and rate pressure product (RPP) were lower and stroke volume (SV) significantly higher after 16 weeks training and 4 weeks detraining: at 50% VO2 max, HR and RPP were lower after 16 weeks training and 4 weeks detraining: at 70% VO2 max, cycle ergometry power, VO2 and arterio‐venous oxygen difference (a ‐ &OV0456;O2) were higher after 16 weeks training. Leg strength and VO2 max increased after 16 weeks training, with leg strength remaining above pre‐training levels after 4‐weeks detraining. Conclusions: Sixteen weeks of strength training significantly improves the cardiovascular function of older men. Therefore strength training not only increases muscular strength and hypertrophy but also provides significant cardiovascular benefits for older individuals.

Resistance training reduces the blood pressure response of older men during submaximum aerobic exercise

ObjectiveThe objective of this study was to determine whether 16 weeks of resistance training (RT) can reduce the blood pressure response and improve the cardiovascular function of men aged 70–80 years during submaximum aerobic exercise. MethodsTwenty-four men aged between 70 and 80 years were randomly assigned to an RT group (n = 12) and control group (n = 12). Training consisted of three sets of six to 10 repetitions at 70–90% of one repetition maximum, three times per week, on an incline squat machine for 16 weeks. Blood pressure and cardiovascular function were assessed during submaximum cycle exercise at 40 W, and 50 and 70% of maximum oxygen consumption (VO2max) before training and after 16 weeks of training. Leg strength and VO2max were assessed every 4 weeks of the 16-week study. ResultsAt 40 W, heart rate, systolic blood pressure, and rate pressure product were lower and stroke volume was significantly higher after 16 weeks of training. At 50% VO2max, heart rate and rate pressure product were lower after 16 weeks of training and at 70% VO2max, cycle ergometry power, VO2, and arterio-venous oxygen difference were higher after 16 weeks of training. Leg strength significantly increased after 16 weeks of training. ConclusionSixteen weeks of RT significantly reduces the blood pressure response and improves the cardiovascular function of older men during submaximum aerobic exercise. Therefore, RT not only increases muscular strength and hypertrophy but also provides significant cardiovascular benefits for older individuals.

The hormonal response of older men to sub-maximum aerobic exercise: The effect of training and detraining

The hormonal response of 32 older men (70-80years) to a bout of sub-maximum aerobic exercise was examined before, after 16weeks of resistance or aerobic training and again after 4weeks of detraining. Blood samples were obtained at rest and immediately post sub-maximum exercise (30min @ 70% VO(2) max) to determine the concentrations of growth hormone (GH), insulin-like growth factor-1 (IGF-1), testosterone (Test), sex hormone-binding globulin (SHBG) and the calculation of free testosterone (FT). Both training groups had significant increases in leg strength and VO(2) max after 16weeks training but leg strength and VO(2) max returned to pre-training levels in the aerobic training and resistance training groups, respectively. During the 20week study there was no change in resting concentrations of any hormones among the three groups. There was no increase in GH, IGF-1 or SHBG immediately post sub-maximum exercise in any of the groups before training, after 16weeks training or after 4weeks detraining. Testosterone and FT increased immediately post sub-maximum exercise within all groups before training, after 16weeks training and after 4weeks detraining with the increase in Test and FT higher after 16weeks of resistance training compared to before training and after 4weeks detraining within the resistance training group. The increased responsiveness of Test and FT after 16weeks of resistance training was lost after 4weeks of detraining. Our results indicate that some physiological and hormonal adaptations gained after 16weeks training are lost after only 4weeks detraining.

Do compression garments enhance the active recovery process after high-intensity running?

Lovell, DI, Mason, DG, Delphinus, EM, and McLellan, CP. Do compression garments enhance the active recovery process after high-intensity running? J Strength Cond Res 25(12): 3264–3268, 2011—This study examined the effect of wearing waist-to-ankle compression garments (CGs) on active recovery after moderate- and high-intensity submaximal treadmill running. Twenty-five male semiprofessional rugby league players performed two 30-minute treadmill runs comprising of six 5-minute stages at 6 km·h−1, 10 km·h−1, approximately 85% &OV0312;O2max, 6 km·h−1 as a recovery stage followed by approximately 85% &OV0312;O2max and 6 km·h−1 wearing either CGs or regular running shorts in a randomized counterbalanced order with each person acting as his own control. All stages were followed by 30 seconds of rest during which a blood sample was collected to determine blood pH and blood lactate concentration [La−]. Expired gases and heart rate (HR) were measured during the submaximal treadmill tests to determine metabolic variables with the average of the last 2 minutes used for data analysis. The HR and [La−] were lower (p ≤ 0.05) after the first and second 6 km·h−1 recovery bouts when wearing CGs compared with when wearing running shorts. The respiratory exchange ratio (RER) was higher and [La−] lower (p ≤ 0.05) after the 10 km·h−1 stage, and only RER was higher after both 85% &OV0312;O2max stages when wearing CGs compared with when wearing running shorts. There was no difference in blood pH at any exercise stage when wearing the CGs and running shorts. The results of this study indicate that the wearing of CGs may augment the active recovery process in reducing [La−] and HR after high-intensity exercise but not effect blood pH. The ability to reduce [La−] and HR has important consequences for many sports that are intermittent in nature and consist of repeated bouts of high-intensity exercise interspersed with periods of low-intensity exercise or recovery.

The contribution of energy systems during the upper body Wingate anaerobic test.

The purpose of this study was to measure the contribution of the aerobic, anaerobic lactic, and alactic systems during an upper body Wingate Anaerobic test (WAnT). Oxygen uptake and blood lactate were measured before, during, and after the WAnT and body composition analyzed by dual-energy X-ray absorptiometry. The contribution of the energy systems was 11.4% ± 1.4%, 60.3% ± 5.6%, and 28.3% ± 4.9% for the aerobic, anaerobic lactic, and alactic systems, respectively.