ADAPTations to low load blood flow restriction exercise versus conventional heavier load resistance exercise in UK military personnel with persistent knee pain: protocol for the ADAPT study, a multi-centre randomized controlled trial

Robyn P. Cassidy, Kieran M. Lunt, Russell J. Coppack, Alexander N Bennett, James L. J. Bilzon, M Polly Mcguigan, Natalie Egginton, Edward Sellon, Jo Day, Peter Ladlow

Research output: Contribution to journalArticlepeer-review


BACKGROUND: Muscle atrophy, muscle weakness and localised pain are commonly reported following musculoskeletal injury (MSKI). To mitigate this risk and prepare individuals to return to sport or physically demanding occupations, resistance training (RT) is considered a vital component of rehabilitation. However, to elicit adaptations in muscle strength, exercise guidelines recommend lifting loads ≥ 70% of an individual's one repetition maximum (1-RM). Unfortunately, individuals with persistent knee pain are often unable to tolerate such high loads and this may negatively impact the duration and extent of their recovery. Low load blood flow restriction (LL-BFR) is an alternative RT technique that has demonstrated improvements in muscle strength, hypertrophy, and pain in the absence of high mechanical loading. However, the effectiveness of high-frequency LL-BFR in a residential rehabilitation environment remains unclear. This study will compare the efficacy of high frequency LL-BFR to 'conventional' heavier load resistance training (HL-RT) on measures of physical function and pain in adults with persistent knee pain.

METHODS: This is a multicentre randomised controlled trial (RCT) of 150 UK service personnel (aged 18-55) admitted for a 3-week residential rehabilitation course with persistent knee pain. Participants will be randomised to receive: a) LL-BFR delivered twice daily at 20% 1-RM or b) HL-RT three-times per week at 70% 1-RM. Outcomes will be recorded at baseline (T1), course discharge (T2) and at three-months following course (T3). The primary outcome will be the lower extremity functional scale (LEFS) at T2. Secondary outcomes will include patient reported perceptions of pain, physical and occupational function and objective measures of muscle strength and neuromuscular performance. Additional biomechanical and physiological mechanisms underpinning both RT interventions will also be investigated as part of a nested mechanistic study.

DISCUSSION: LL-BFR is a rehabilitation modality that has the potential to induce positive clinical adaptations in the absence of high mechanical loads and therefore could be considered a treatment option for patients suffering significant functional deficits who are unable to tolerate heavy load RT. Consequently, results from this study will have a direct clinical application to healthcare service providers and patients involved in the rehabilitation of physically active adults suffering MSKI.

TRIAL REGISTRATION: reference number, NCT05719922.

Original languageEnglish
Article number580
JournalBMC Musculoskeletal Disorders
Issue number1
Publication statusPublished - 17 Jul 2023

Bibliographical note

Funding Information:
The authors wish to thank the clinical staff at each study centre location, including: Mr Gordon McKay (RRU Edinburgh); Mr Robert Jones, Mr Mark Perkins and Mr David Church (RRU St Athan); Mr Neil Strawbridge (RRU Cranwell); Miss Rachel Spanner and Maj Helen Stammers (RRU Colchester) and Mr Oliver Rosenstock and Mr Christopher Hughes (RRU Aldershot) for supporting the conduct of this research in a busy clinical setting. The authors also acknowledge the efforts of administrative support staff at each study centre location, in particular the ADAPT Study lead administrator Fiona Miller based at the UK Defence Medical Rehabilitation Centre (DMRC), Stanford Hall. Disseminations of research findings will be primarily driven via publications and conference proceeding. All author eligibility criteria will be based on meaningful contribution to the manuscript in accordance with International Committee of Medical Journal Editors (ICMJE) guidelines.


  • Defence rehabilitation
  • Knee injury
  • Lower limb
  • Musculoskeletal health
  • Occlusion training
  • Occupational rehabilitation
  • Return-to-duty
  • Strength training
  • Training load

ASJC Scopus subject areas

  • Rheumatology
  • Orthopedics and Sports Medicine


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