Paul G. Montgomery

Quantifying movement demands of AFL football using GPS tracking

Global positioning system (GPS) monitoring of movement patterns is widespread in elite football including the Australian Football League (AFL). However documented analysis of this activity is lacking. We quantified the movement patterns of AFL football and differences between nomadic (midfield), forward and defender playing positions, and determined whether the physical demands have increased over a four season period. Selected premiership games were monitored during the 2005 (n=80 game files), 2006 (n=244), 2007 (n=632) and 2008 (n=793) AFL seasons. Players were fitted with a shoulder harness containing a GPS unit. GPS data were downloaded after games and the following measures extracted: total distance (km), time in various speed zones, maximum speed, number of surges, accelerations, longest continuous efforts and a derived exertion index representing playing intensity. In 2008 nomadic players covered per game 3.4% more total distance (km), had 4.8% less playing time (min), a 17% higher exertion index (per min), and 23% more time running >18kmh(-1) than forwards and defenders (all p<0.05). Physical demands were substantially higher in the 2008 season compared with 2005: an 8.4% increase in mean speed, a 14% increase in intensity (exertion index) and a 9.0% decrease in playing time (all p<0.05). Nomadic players in AFL work substantially harder than forwards and defenders in covering more ground and at higher running intensities. Increases in the physical demands of AFL football were evident between 2005 and 2008. The increasing speed of the game has implications for game authorities, players and coaching staff.

The effect of recovery strategies on physical performance and cumulative fatigue in competitive basketball

Abstract To evaluate the effectiveness of recovery strategies on physical performance during a 3-day tournament style basketball competition, 29 male players (mean age 19.1 years, s = 2.1; height 1.84 m, s = 0.34; body mass 88.5 kg, s = 14.7) were assigned to one of three treatment groups: carbohydrate + stretching (7.7 g · kg −1 · day −1, s = 1.7; ‘n = 9), cold water immersion (11°C, 5 × 1; n = 10) or full leg compression garments (18 mmHg, ∼18 h; n = 10). Effects of the recovery strategies on pre–post tournament performance tests were expressed as the mean change (% ± standard deviation of the change score). Changes and differences were standardized for accumulated game time, assessed against the smallest worthwhile change for each test, and reported qualitatively. Accumulated fatigue was evident over the tournament with small to moderate impairments in performance tests. Sprint and agility performance decreased by 0.7% (s = 1.3) and 2.0% (s = 1.9) respectively. Vertical jump decreased substantially after the first day for all treatments, and remained suppressed post-tournament. Cold water immersion was substantially better in maintaining 20-m acceleration with only a 0.5% (s = 1.4) reduction in 20-m time after 3 days compared with a 3.2% (s = 1.6) reduction for compression. Cold water immersion (−1.4%, s = 1.7) and compression (−1.5%, s = 1.7) showed similar substantial benefits in maintaining line-drill performance over the tournament, whereas carbohydrate + stretching elicited a 0.4% (s = 1.8) reduction. Sit-and-reach flexibility decreased for all groups, although cold water immersion resulted in the smallest reduction in flexibility. Basketball tournament play elicited small to moderate impairments in physical test performance. In conclusion, cold water immersion appears to promote better restoration of physical performance measures than carbohydrate + stretching routines and compression garments.

Relationships Between Repeated Sprint Testing, Speed, and Endurance

Pyne, DB, Saunders, PU, Montgomery, PG, Hewitt, AJ, and Sheehan, K. Relationships between repeated sprint testing, speed, and endurance. J Strength Cond Res 22(5): 1633-1637, 2008-Repeated sprint testing is gaining popularity in team sports, but the methods of data analysis and relationships to speed and endurance qualities are not well described. We compared three different methods for analyzing repeated sprint test results, and we quantified relationships between repeated sprints, short sprints, and endurance test scores. Well-trained male junior Australian Football players (n = 60, age 18.1 ± 0.4 years, height 1.88 ± 0.07 m, mass 82.0 ± 8.1 kg; mean ± SD) completed a 6 × 30-m repeated sprint running test on a 20-second cycle, a 20-m sprint test (short sprint), and the 20-m multistage shuttle run for endurance. Repeated sprint results were evaluated in three ways: total time for all six sprints (TOTAL), percent change from predicted times (PRED) from the fastest 30-m sprint time, and percent change from first to last sprint (CHANGE). We observed a very large decrement (CHANGE 6.3 ± 0.7%, mean ± 90% confidence limits) in 30-m performance from the first to last sprint (4.16 ± 0.10 to 4.42 ± 0.11 seconds, mean ± SD). Results from TOTAL were highly correlated with 20-m sprint and 20-m multistage shuttle run tests. Performance decrements calculated by PRED were highly correlated with TOTAL (r = 0.91), but neither method was directly comparable with CHANGE (r = −0.23 and r = 0.12 respectively). TOTAL was moderately correlated with fastest 20-m sprint time (r = 0.66) but not the 20-m multistage shuttle run (r = −0.20). Evaluation of repeated sprint testing is sensitive to the method of data analysis employed. The total sprint time and indices of the relative decrement in performance are not directly interchangeable. Repeated sprint ability seems more related to short sprint qualities than endurance fitness.

Muscle damage, inflammation, and recovery interventions during a 3-day basketball tournament

Abstract Cold water immersion and compression garments are now popular strategies for post-exercise recovery. However, little information exists on the effectiveness of these strategies to minimize muscle damage, or any impact they may have on biomarker clearance after team sport competition. The main aim of this study was to investigate the time course of muscle damage markers and inflammatory cytokines during basketball tournament play. We also wished to examine if cold water immersion and compression recovery strategies ameliorate any post-game increases of these biomarkers, compared with traditional refuelling and stretching routines. Male basketball players (age 19.1 years, s=2.1; height 1.91 m, s=0.09; body mass 87.9 kg, s=15.1) were asked to compete in a three-day tournament playing one game each day. Players were assigned to one of three recovery treatments: carbohydrate+stretching (control, n=9), cold-water immersion at 11°C for 5×1 min (n=10); or full-leg compression at 18 mmHg for ∼18 h (n=10). Players received their treatment after each game on three consecutive days. Venous blood samples were assayed before the tournament and at 10 min, 6 h, and 24 h after each game for concentrations of the muscle damage markers fatty-acid binding protein (FABP), creatine kinase, and myoglobin; interleukin-6 (IL-6) and interleukin-10 (IL-10) were also assayed. Inferences were based on log-transformed concentrations. Post-game increases in damage markers were clear and very large for FABP after the cold water immersion (3.81 ×/÷ 1.19, factor mean ×/÷ factor s), compression (3.93 ×/÷ 1.46), and control (4.04 ×/÷ 1.19) treatments. Increases in myoglobin were also clear and very large after the cold water immersion (3.50 ×/÷ 1.35), compression (3.66 ×/÷ 1.48), and control (4.09 ×/÷ 1.18) treatments. Increases in creatine kinase were clear but small after the cold water immersion (1.30 ×/÷ 1.03), compression (1.25 ×/÷ 1.39), and control (1.42 ×/÷ 1.15) treatments, with small or unclear differences between treatments. There were clear moderate to large post-game increases in IL-6 for cold water immersion (2.75 ×/÷ 1.37), compression (3.43 ×/÷ 1.52), and control (3.47 ×/÷ 1.49). Increases in IL-10 were clear and moderate for cold water immersion (1.75 ×/÷ 1.43), but clear and large after the compression (2.46 ×/÷ 1.79) and control (2.32 ×/÷ 1.41) treatments. Small decreases in IL-6 and IL-10 were observed with cold water immersion compared with the compression and control treatments, with unclear effects between treatments over the tournament. There was no clear benefit from any recovery treatment post-game, as the differences between treatments for all biomarker measures were small or unclear. Pre- to post-tournament increases in FABP, myoglobin, and creatine kinase were clearly small to moderate. There were also small to moderate differences between cold water immersion and the compression (0.85 ×/÷ 1.21) and control (0.76 ×/÷ 1.26) treatments for the post-tournament measures compared with pre-tournament. Pre- to post-tournament changes for IL-6 and IL-10 were unclear, as were the differences between treatments for both cytokines. Tournament basketball play elicits modest elevations of muscle damage markers, suggesting disruption of myocyte membranes in well-trained players. The magnitude of increase in muscle damage markers and inflammatory cytokines post-game ranged from small for creatine kinase, to large for IL-6 and IL-10, to very large for FABP and myoglobin. Cold water immersion had a small to moderate effect in decreasing FABP and myoglobin concentrations after a basketball tournament compared with the compression and control treatments.

VALIDATION OF HEART RATE MONITOR-BASED PREDICTIONS OF OXYGEN UPTAKE AND ENERGY EXPENDITURE

Montgomery, PG, Green, DJ, Etxebarria, N, Pyne, DB, Saunders, PU, and Minahan, CL. Validation of heart rate monitor-based predictions of oxygen uptake and energy expenditure. J Strength Cond Res 23(5): 1489-1495, 2009-To validate &OV0312;o2 and energy expenditure predictions by the Suunto heart rate (HR) system against a first principle gas analysis system, well-trained male (n = 10, age 29.8 ± 4.3 years, &OV0312;o2 65.9 ± 9.7 ml·kg−1·min−1) and female (n = 7, 25.6 ± 3.6 years, 57.0 ± 4.2 ml·kg−1·min−1) runners completed a 2-stage incremental running test to establish submaximal and maximal oxygen uptake values. Metabolic cart values were used as the criterion measure of &OV0312;o2 and energy expenditure (kJ) and compared with the predicted values from the Suunto software. The 3 levels of software analysis for the Suunto system were basic personal information (BI), BI + measured maximal HR (BIhr), and BIhr + measured &OV0312;o2 (BIhr + v). Comparisons were analyzed using linear regression to determine the standard error of the estimate (SEE). Eight subjects repeated the trial within 7 days to determine reliability (typical error [TE]). The SEEs for oxygen consumption via BI, BIhr, and BIhr + v were 2.6, 2.8, and 2.6 ml·kg−1·min−1, respectively, with corresponding percent coefficient of variation (%CV) of 6.0, 6.5, and 6.0. The bias compared with the criterion &OV0312;o2 decreased from −6.3 for BI, −2.5 for BIhr, to −0.9% for BIhr + v. The SEE of energy expenditure improved from BI (6.74 kJ) to BIhr (6.56) and BIhr + v (6.14) with corresponding %CV of 13.6, 12.2, and 12.7. The TE values for &OV0312;o2 were ∼0.60 ml·kg−1·min−1 and ∼2 kJ for energy expenditure. The %CV for &OV0312;o2 and energy expenditure was ∼1 to 4%. Although reliable, basic HR-based estimations of &OV0312;o2 and energy expenditure from the Suunto system underestimated &OV0312;o2 and energy expenditure by ∼6 and 13%, respectively. However, estimation can be improved when maximal HR and &OV0312;o2 values are added to the software analysis.

Seasonal progression and variability of repeat-effort line-drill performance in elite junior basketball players

Abstract To determine gender differences, positional differences, and patterns of change in the performance of the basketball line-drill test, 93 male (mean age 16.8 years, s = 1.1) and 95 female (mean age 16.5 years, s = 1.0) basketball players undertook 516 line-drill tests over a 5-year period. Log-transformed performance times were analysed using a mixed model that included quadratic within-participant fixed effects for time in the season and time in the programme. Changes and differences were standardized for interpretation of magnitudes. Mean performance times were 28.0 s (s = 1.3) for males and 30.4 s (s = 1.3) for females. The mean pattern of change in performance within a season differed substantially between the sexes and playing positions: male guards and female centres showed moderate to very large improvements mid-season of 1.1% and 3.5% respectively (90% confidence limits ±2.1% and ±3.0%), while female guards and male forwards showed large to very large decrements of −1.6% (±2.6%) and −2.4% (±2.0%). Over 3 years, males improved performance across all three playing positions by 1.4% (±1.3%) and females by 2.9% (±1.4%). Males improved performance by 0.2% (±0.5%) per year, whereas the performance of females deteriorated by 0.6% (±0.4%) per year. The differing patterns of performance change presumably reflect variations in training and competition loads, with short-term fluctuations in performance being managed to promote longer-term improvements.

The Effect of Interchange Rotation Period and Number on Australian Football Running Performance.

Abstract Montgomery, PG, and Wisbey, B. The effect of interchange rotation period and number on Australian Football running performance. J Strength Cond Res 30(7): 1890–1897, 2016—To determine the effect of on-field rotation periods and total number of game rotations on Australian Football running performance, elite Australian Football players (n = 21, mean ± SD; 23.2 ± 1.7 years; 183.5 ± 3.7 cm; 83.2 ± 4.5 kg) had Global Positioning System game data from 22 rounds divided into a total of 692 on-field playing periods. These periods were allocated into time blocks of 2:00-minute increments, with the log transformed percentage differences in running performance (m·min−1) between blocks analyzed by effect size and meaningful differences. A total of 7,730 game rotation and associated average m·min−1 combinations collected over 3 Australian Football seasons were also assessed by effect size and meaningful differences. Running capacity decreases after 5:00 minutes by ∼3% for each 2:00 minutes of on-field time up to 9:00 minutes, with variable responses between positions up to 6.7% for nomadic players. For each rotation less than 6 per game, clear small-to-moderate decreases up to 3.6% in running capacity occurred per rotation. To maintain a high level of running capacity, shorter on-field periods are more effective in Australian Football; however, players and coaches should be aware that with interchange restriction, slightly longer on-field periods achieve similar results.