The study is a 12-week human study where 60 participants with chronic patellar tendinopathy (more than 3 months symptoms duration) are randomised to undergo 12 weeks of targeted resistance exercise either in the morning or in the late afternoon. The overall aim is to investigate when the best time of the day to perform muscular strength training therapy towards tendinopathy is. The study will also include 10 healthy controls who will not perform any exercise training.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
70
The exercise will be started at 60% of 1 repetition maximum (RM) and progressed to 75% of 1 RM during the first 3 weeks and maintained throughout the intervention period. The exercise will be performed slowly (6 s/ repetition).
Institute of Sports Medicine Copenhagen
Copenhagen NV, Capital Region, Denmark
RECRUITINGPatient perception VISA-P
Change in Victorian Institute of Sports Assessment - patella (VISA-P) total score. The VISA-P asses symptoms, function and the ability to participate in sport. It consists of 8 questions, with a maximum score of 100 indicating the person is asymptomatic and fully per-forming and lower scores indicating more symptoms and limitations of function and activity.
Time frame: Change from baseline at week 12.
Patient perception VISA-P truncated
Change in Victorian Institute of Sports Assessment - patella (VISA-P) truncated score. The truncated score only including questions 2-6, with a maximum score of 50. Lower scores indicating more symptoms and limitations of function and activity.
Time frame: Change from baseline at week 12 and 52.
Patient perception VISA-P
Change in Victorian Institute of Sports Assessment - patella (VISA-P) total score. The VISA-P asses symptoms, function and the ability to participate in sport. It consists of 8 questions, with a maximum score of 100 indicating the person is asymptomatic and fully per-forming and lower scores indicating more symptoms and limitations of function and activity.
Time frame: Change from baseline at week 52.
Self-reported improvement (GROC)
Self-reported improvement after treatment will be evaluated by the Global Rating of change (GROC) on a 7-point Likert scale ranging from 'much improved' to 'much worse'.
Time frame: Change from baseline at week 12 and 52.
Self-reported satisfaction (PASS)
Self-evaluated satisfaction with treatment result will be evaluated by Patient Acceptable Symptom State (PASS) on a 5-point Likert scale ranging from 'very satisfied' to 'very unsatisfied'.
Time frame: Change from baseline at week 12 and 52.
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Counter movement jump height
Jump height during counter movement jump test will be used to assess patellar tendinopathy caused functional deficits.
Time frame: Change from baseline at week 52.
Pain during single-leg decline squat (SLDS)
Participants performed a decline squat on a 25°decline board and reported pain using an 11 point numeric rating scale (NRS) upon completion, with 10 being the worst imaginable pain and 0 denoting no pain.
Time frame: Change from baseline at week 12 and 52.
Ultrasonography - tendon thickness
Grey scale ultrasonography will be used for evaluation of patellar tendon thickness.
Time frame: Change from baseline at week 12 and 52.
Ultrasonography - power Doppler
Doppler ultrasonography will be used for evaluation of patellar tendon vascularization/blood flow.
Time frame: Change from baseline at week 12 and 52.
Lean mass by dual-energy X-ray absorptiometry
Change in quadriceps lean muscle mass by DEXA.
Time frame: Change from baseline at week 12.
Expression of circadian clock genes
Changes in expression of circadian clock genes and known tendon clock target genes by tendon tissue biopsies measured in the bulk RNA by RNA sequencing and reverse transcription-quantitative polymerase chain reaction (RT-qPCR).
Time frame: Change from baseline at week 12, compared to healthy controls.
Expression of extracellular matrix (ECM) and ECM regulator genes
Changes in expression of ECM and ECM regulator genes by tendon tissue biopsies measured in the bulk RNA by RNA sequencing and reverse transcription-quantitative polymerase chain reaction (RT-qPCR).
Time frame: Change from baseline at week 12, compared to healthy controls.
Global expression of genes
Unbiased examination of global changes in expression of genes by tendon tissue biopsies measured in the bulk RNA by RNA sequencing.
Time frame: Change from baseline at week 12, compared to healthy controls.
Histochemical staining of tendon sections
Morphology of tendon tissue regions, including cells and blood vessels, measured by histochemical and immunohistochemical stainings of tendon tissue biopsies.
Time frame: Change from baseline at week 12, compared to healthy controls.
Spatial changes of gene expression
Unbiased examination of global changes in expression of genes in regions of interests of tendon tissue biopsies measured by spatial transcriptomics.
Time frame: Change from baseline at week 12, compared to healthy controls.
Spatial changes of extracellular matrix protein levels
Unbiased examination of global changes in levels of extracellular matrix proteins in regions of interests of tendon tissue biopsies measured by spatial transcriptomics.
Time frame: Change from baseline at week 12, compared to healthy controls.
Blood samples
Identification of potential biomarkers of tendon injury and repair by metabolomics and proteomics.
Time frame: Change from baseline at week 12, compared to healthy controls.