Abstract
Introduction: Hamstring strain injury (HSI) rates have been the greatest injury concern in the Australian Football League for the past 20 years. History of HSI and fatigue are regularly discussed in the literature as risk factors, while the influence of lumbar spine function has remained largely theoretical. The purpose of this study was to assess whether fatigue induced changes to the forces acting on the lumbar spine exist in Australia Rules Football (ARF) players both with and without a history of HSI.
Methods: Thirty community level ARF players (age, 24.5 ± 5.3 years, height 183.7 ± 7.1 cm, mass 85.4 ± 9.4 kg), 19 controls with no previous HSI and 11 with a HSI within the previous two years, undertook a laboratory-based game protocol simulating the running requirements of an ARF match. The game protocol consisted of a warm-up (WU) and four quarters (Q1–Q4), each consisting of 39 pre-defined speed and distance changes using a programmed treadmill, followed by 10 maximal over ground sprints to conclude each quarter. The over ground sprints were used to assess kinetics, kinematics, and fatigue status of each participant. As a means of assessing lumbar spine function, joint moments were assessed at both L5-S1 and T12-L1.
Results: During stance phase, the control group showed an increased T12-L1 flexion joint moment from WU to Q3 (p = 0.01), and a reduced T12-L1 extension joint moment from Q3 to Q4 (p = 0.03). The history group, also during stance phase, displayed increased L5-S1 flexion, L5-S1 extension, T12-L1 extension (all p < 0.00), and T12-L1 flexion joint moments (p = 0.01) at Q4 when compared to WU. When compared to WU, an average of sagittal plane peak net joint moments at L5-S1 and T12-L1 showed the control group to peak during Q3 with an 18.1% increase, and the history group to peak at Q4 with a 53.3% increase. Significant increases to ground reaction force impulses were noted during every quarter following WU.
Discussion: Peak net joint moments reflect the net effect of agonists and antagonists on a joint, expressing the force producing movement at a joint. The findings of this study confirm game fatigue in community level ARF players increases sagittal trunk joint moments up to Q3, after which forces reduce for those without previous HSI, and increase for those with a history of HSI. This suggests that individuals with a HSI history exhibit reduced loading absorption strategies in the later stages of a game.
Methods: Thirty community level ARF players (age, 24.5 ± 5.3 years, height 183.7 ± 7.1 cm, mass 85.4 ± 9.4 kg), 19 controls with no previous HSI and 11 with a HSI within the previous two years, undertook a laboratory-based game protocol simulating the running requirements of an ARF match. The game protocol consisted of a warm-up (WU) and four quarters (Q1–Q4), each consisting of 39 pre-defined speed and distance changes using a programmed treadmill, followed by 10 maximal over ground sprints to conclude each quarter. The over ground sprints were used to assess kinetics, kinematics, and fatigue status of each participant. As a means of assessing lumbar spine function, joint moments were assessed at both L5-S1 and T12-L1.
Results: During stance phase, the control group showed an increased T12-L1 flexion joint moment from WU to Q3 (p = 0.01), and a reduced T12-L1 extension joint moment from Q3 to Q4 (p = 0.03). The history group, also during stance phase, displayed increased L5-S1 flexion, L5-S1 extension, T12-L1 extension (all p < 0.00), and T12-L1 flexion joint moments (p = 0.01) at Q4 when compared to WU. When compared to WU, an average of sagittal plane peak net joint moments at L5-S1 and T12-L1 showed the control group to peak during Q3 with an 18.1% increase, and the history group to peak at Q4 with a 53.3% increase. Significant increases to ground reaction force impulses were noted during every quarter following WU.
Discussion: Peak net joint moments reflect the net effect of agonists and antagonists on a joint, expressing the force producing movement at a joint. The findings of this study confirm game fatigue in community level ARF players increases sagittal trunk joint moments up to Q3, after which forces reduce for those without previous HSI, and increase for those with a history of HSI. This suggests that individuals with a HSI history exhibit reduced loading absorption strategies in the later stages of a game.
| Original language | English |
|---|---|
| Pages | 16-16 |
| Number of pages | 1 |
| DOIs | |
| Publication status | Published - 2018 |