The Impact of Unilateral Lumbar Mobilisations on Hamstring Strength and Failure Point of the Hamstring Nordic Exercise
Condition: Hamstring Injury
Study type: Interventional

Summary: 
      The aim of this study is to build on previous published work, which has indicated lumbar
      mobilisations have the ability to increase hamstring extensibility and decrease muscle
      activity. The primary aim of this project is investigate if lumbar mobilisations have an
      affect on the Nordic Hamstring exercise.

      Aim: To investigate the short-term effects L4 and L5 Unilateral Posterior Anterior (UPA)
      Mobilisations on the lumbar spine on the Nordic Hamstring Exercise. Measures will include
      hamstring peak torque, sEMG activity and knee angle at first rapid change in angular
      acceleration.
    

Detailed description: 
      The study aims to investigate the short-term effects L4 and L5 Unilateral Posterior Anterior
      (UPA) Mobilisations on the lumbar spine on the Nordic Hamstring Exercise. Measures will
      include hamstring peak torque, sEMG activity and knee angle at first rapid change in angular
      acceleration.

      Recruitment will take place via flyer and email. All testing will take place in the biodex
      laboratory at Teesside University. Due to the nature of the cross-over design participants
      will attend the laboratory six times, two for familiarisation sessions, and a remaining four
      testing session all 72 hours apart. The four testing sessions will contain two control and
      two intervention sessions attended in a randomised order.

      Following recruitment participants will be required to complete a medical questionnaire and
      sign a consent form following reading the participant information sheet.

      The Nordic Hamstring exercise will be performed by each participant across the intervention
      and control conditions. Participants will watch a video of a subject completing the Nordic
      exercise program. They will also receive the following verbal instructions:

      'Players start in a kneeling position, with the torso from the knees upward held rigid and
      straight. The training partner ensures that the player's feet are in contact with the ground
      throughout the exercise by applying pressure to the player's heels/lower legs. The player
      then lowers his upper body to the ground, as slowly as possible to maximize loading in the
      eccentric phase. Hands and arms are used to break his forward fall and to push him back up
      after the chest has touched the ground, to minimize loading in the concentric phase (Mjølsne
      et al, 2005; Petersen et al, 2011).

      All participants will be given the opportunity to ask questions as necessary.

      A standardised warm-up on an ergometer will be undertaken for 5 minutes at 60% max resting
      heart rate.

      Following the warm-up all participants will familiarise themselves with the Nordic Hamstring
      Exercise on the hamstring solo equipment. They will be able to practice up to 8 repetitions.
      This data will be used for a reliability study to understand the number of required
      repetitions for the main study.

      During testing participants will attend the same laboratory for the remaining four testing
      sessions. They will receive two intervention sessions, when the lumbar mobilisations will be
      performed, and two when the control is administered.

      The same warm-up undertaken during the familiarisation session will be undertaken prior to
      testing.

      The intervention will consist of unilateral lumbar mobilisations at the L4 and L5 level in a
      Posterior Anterior direction. The side of the mobilisation will be determined by dominate leg
      - considered the kicking foot. The mobilisations will be administered by a physiotherapist
      with at least 12 years clinical experience. Teksan grip sensors will be worn by the
      physiotherapist to calculate the force applied to the participant. Grade three mobilisations
      will be applied for a one minute period three times at both L4 and L5 level.

      For the control, all participants will be laid prone on the medical plinth in the same
      position will no mobilisations administered.

      Outcome measures will include collection of hamstring peak force data, sEMG of the Biceps
      Femoris, 3D Motion capture data and subjective likert scale of exercise difficulty.
    

Intervention name(s): Lumbar Mobilisations
Intervention type(s): Other
Intervention description(s): The intervention will consist of unilateral lumbar mobilisations at the L4 and L5 level in a Posterior Anterior direction. The side of the mobilisation will be determined by dominant leg - considered the kicking foot. The mobilisations will be administered by a physiotherapist with at least 10 years clinical experience. Teksan grip sensors will be worn by the physiotherapist to calculate the force applied to the participant. Grade three mobilisations will be applied for a one minute period three times at both L4 and L5 level. Each level will be determined by a passive physiological intervertebral movement. Participants will receive the mobilisations at L5 first for one minute followed by L4. This is an appropriate dose for mobilisation application (Maitland, 2013). This process will be carried out three times.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment