title: Local and Systemic Changes in Pain Sensitivity After 4 Weeks of Calf Muscle Stretching in a Nonpainful Population: A Randomized Trial.
abstract: Stretching is often used in clinical practice for a variety of purposes, including pain therapy. The possible mechanism behind the effect of stretching remains to be clarified.
  
  
  
  To investigate whether 4 weeks of unilateral stretching of the calf muscles would affect local and central pain sensitivity.
  
  
  
  This study was a randomized assessor-blinded clinical study. Healthy participants (age 18 to 40) were included and randomized. Participants in the intervention group were instructed to perform 2 stretching exercises targeting the calf muscles; 3 times 30 seconds, 7 days a week for 4 weeks on the dominant leg. Participants in the control group were instructed not to do any stretching for 4 weeks. Pressure pain threshold (PPT) and temporal summation (TS) of pressure pain were measured on the stretched calf, the contra-lateral calf, and contra-lateral lower arm using a computerized cuff algometer. Analyses of variance on the per-protocol population (defined as participants that adhered to the protocol) were used to assess group differences in the changes from baseline.
  
  
  
  Forty healthy volunteers were included, of which 34 participants adhered to the protocol (15 intervention group/19 control group). No statistically significant group differences in the changes from baseline were found regarding PPT and TS measurements for the stretched calf, the contra-lateral calf, and the arm.
  
  
  
  Four weeks of regular stretching of the calf muscles does not affect pressure pain sensitivity, suggesting that pressure pain sensitivity is unaffected by stretching in a healthy population. The mechanisms underlying any benefits of regular stretching remain to be explained.
authors.affiliation: Department of Rheumatology, The Parker Institute, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark.
authors.forename: Cecilie
authors.initials: C
authors.lastname: Bartholdy
authors.affiliation: Department of Rheumatology, The Parker Institute, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark.
authors.forename: Graziella
authors.initials: G
authors.lastname: Zangger
authors.affiliation: Department of Rheumatology, The Parker Institute, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark.
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Hansen
authors.affiliation: Department of Rheumatology, The Parker Institute, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Ginnerup-Nielsen
authors.affiliation: Department of Rheumatology, The Parker Institute, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark.
authors.forename: Henning
authors.initials: H
authors.lastname: Bliddal
authors.affiliation: Department of Rheumatology, The Parker Institute, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark.
authors.forename: Marius
authors.initials: M
authors.lastname: Henriksen
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D052580:Muscle Stretching Exercises / Q000379:methods*; D018482:Muscle, Skeletal / Q000502:physiology; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D011312:Pressure; D011446:Prospective Studies; D055815:Young Adult
keywords: PPT; algometry; muscles stretching; musculoskeletal disease; pain assessment; pain sensitivity; physical therapy; pressure pain threshold; temporal summation