None listed
Conditions
Brief summary
This project will investigate how biceps femoris long head muscle and aponeurosis morphology are influenced after undertaking either a chronic concentric- or eccentric-only resistance training intervention in healthy, recreationally active males. A secondary aim is to determine the impact of these contraction mode specific interventions on biceps femoris long head muscle architecture, diffusion parameters, knee flexor strength, three-dimensional (3D) biomechanics and the musculotendinous demands experienced during running. We hypothesise this muscle-aponeurotic adaptation will be the major driving factor that influences the intrinsic tissue demands during gait (such as musculotendinous strain or fibre strain) instead of due to changes in joint kinematics or kinetics.
Interventions
Healthy, male participants will perform 10 weeks (following randomisation) of either maximal eccentric- or concentric-only knee flexion strength training on an isokinetic dynamometer, consisting of two sessions per week for the duration of the intervention period. This will be conducted at the Movement Analysis Research Laboratory (403.B1.02A) and Exercise Science Research Lab (420.4.12) at Australian Catholic University, Melbourne. Duration of each training session will be approximately 30 mins
Healthy, male participants will perform 10 weeks (following randomisation) of either maximal eccentric- or concentric-only knee flexion strength training on an isokinetic dynamometer, consisting of two sessions per week for the duration of the intervention period. This will be conducted at the Movement Analysis Research Laboratory (403.B1.02A) and Exercise Science Research Lab (420.4.12) at Australian Catholic University, Melbourne. Duration of each training session will be approximately 30 mins and all sessions will be completed one-on-one with the investigator. Across the training period, the volume (number) of contractions will be increased as per the progression outlined below: Week 1: Frequency (days per week) = 2 Sets = 3 Repetitions = 6 Total repetitions = 36 Week 2: Frequency (days per week) = 2 Sets = 3 Repetitions = 6 Total repetitions = 36 Week 3: Frequency (days per week) = 2 Sets = 4 Repetitions = 6 Total repetitions = 48 Week 4: Frequency (days per week) = 2 Sets = 4 Repetitions = 6 Total repetitions = 48 Week 5: Frequency (days per week) = 2 Sets = 5 Repetitions = 6 Total repetitions = 60 Week 6: Frequency (days per week) = 2 Sets = 5 Repetitions = 6 Total repetitions = 60 Week 7: Frequency (days per week) = 2 Sets = 6 Repetitions = 6 Total repetitions = 72 Week 8: Frequency (days per week) = 2 Sets = 6 Repetitions = 6 Total repetitions = 72 Week 9: Frequency (days per week) = 2 Sets = 6 Repetitions = 8 Total repetitions = 96 Week 10: Frequency (days per week) = 2 Sets = 6 Repetitions = 8 Total repetitions = 96 All contractions will be completed at 60deg/sec on the isokinetic dynamometer. All participants will perform two sets of three warm-up efforts at 60deg/sec, in the contraction mode used for their training. For all training repetitions, the concentric training participants will be moved to full knee extension (0deg) by the investigator and will be instructed to maximally flex their knee through to 90deg of knee flexion. The lever arm will then be returned to full knee extension, and the subsequent repetition completed. This will be undertaken until all repetitions are completed in their respective set, with a 30 second rest period between sets. The eccentric training participants will begin with their knee at 90deg of flexion. They will then be instructed to maximally flex against the lever arm until full knee extension is reached (0deg). The the lever arm will then be re-positioned to 90deg of knee flexion for the subsequent contraction. This will be undertaken until all repetitions are completed in each set, with a 30 second rest period between sets. Each training session will be separated by at least 48 hours. Participants will also be asked to refrain from additional hamstring strength training during this intervention period. The participants will be paired according to biceps femoris long head aponeurosis width and randomly assigned to (allocation ratio, 1:1) either concentric- or eccentric-only knee flexor strength training group in a randomly selected limb (the contralateral limb served as a within-participant control).
Sponsors
Australian Catholic University
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
Male
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
Healthy, recreationally active males. This requires participants to have no current lower limb injury. To be deemed recreationally active participants are required to be completing a minimum of two sessions per week of physical activity
Exclusion criteria
Hamstring strain injury within the previous 36 months History of anterior cruciate ligament injury Any other significant lower limb musculoskeletal injury in the previous 12 months Any participants assessed as a moderate risk of an adverse event due to exercise (as measured on the ESSA pre-exercise screening tool) Any participants with a pacemaker, or with a non-MRI-compatible medical device will be excluded from participation.
Outcome results
None listed