title: Efficacy of progressive aquatic resistance training for tibiofemoral cartilage in postmenopausal women with mild knee osteoarthritis: a randomised controlled trial.
abstract: To study the efficacy of aquatic resistance training on biochemical composition of tibiofemoral cartilage in postmenopausal women with mild knee osteoarthritis (OA).
  
  
  
  Eighty seven volunteer postmenopausal women, aged 60-68 years, with mild knee OA (Kellgren-Lawrence grades I/II and knee pain) were recruited and randomly assigned to an intervention (n = 43) and control (n = 44) group. The intervention group participated in 48 supervised aquatic resistance training sessions over 16 weeks while the control group maintained usual level of physical activity. The biochemical composition of the medial and lateral tibiofemoral cartilage was estimated using single-slice transverse relaxation time (T2) mapping and delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC index). Secondary outcomes were cardiorespiratory fitness, isometric knee extension and flexion force and knee injury and OA outcome (KOOS) questionnaire.
  
  
  
  After 4-months aquatic training, there was a significant decrease in both T2 -1.2 ms (95% confidence interval (CI): -2.3 to -0.1, P = 0.021) and dGEMRIC index -23 ms (-43 to -3, P = 0.016) in the training group compared to controls in the full thickness posterior region of interest (ROI) of the medial femoral cartilage. Cardiorespiratory fitness significantly improved in the intervention group by 9.8% (P = 0.010).
  
  
  
  Our results suggest that, in postmenopausal women with mild knee OA, the integrity of the collagen-interstitial water environment (T2) of the tibiofemoral cartilage may be responsive to low shear and compressive forces during aquatic resistance training. More research is required to understand the exact nature of acute responses in dGEMRIC index to this type of loading. Further, aquatic resistance training improves cardiorespiratory fitness.
  
  
  
  ISRCTN65346593.
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland. Electronic address: matti.munukka@jyu.fi.
authors.forename: M
authors.initials: M
authors.lastname: Munukka
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland. Electronic address: ben.waller@jyu.fi.
authors.forename: B
authors.initials: B
authors.lastname: Waller
authors.affiliation: Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia. Electronic address: t.rantalainen@deakin.edu.au.
authors.forename: T
authors.initials: T
authors.lastname: Rantalainen
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland; Department of Physical Medicine and Rehabilitation, Central Finland Central Hospital, Jyväskylä, Finland. Electronic address: arja.h.hakkinen@jyu.fi.
authors.forename: A
authors.initials: A
authors.lastname: Häkkinen
authors.affiliation: Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland; Medical Research Center, University of Oulu and Oulu University Hospital. Electronic address: miika.nieminen@oulu.fi.
authors.forename: M T
authors.initials: MT
authors.lastname: Nieminen
authors.affiliation: Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland. Electronic address: eveliina.lammentausta@oulu.fi.
authors.forename: E
authors.initials: E
authors.lastname: Lammentausta
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland. Electronic address: urho.m.kujala@jyu.fi.
authors.forename: U M
authors.initials: UM
authors.lastname: Kujala
authors.affiliation: Department of Surgery, Central Finland Central Hospital, Jyväskylä, Finland. Electronic address: juha.paloneva@ksshp.fi.
authors.forename: J
authors.initials: J
authors.lastname: Paloneva
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland; Gerontology Research Center, University of Jyväskylä, Finland. Electronic address: sarianna.sipila@jyu.fi.
authors.forename: S
authors.initials: S
authors.lastname: Sipilä
authors.affiliation: Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland. Electronic address: arttu.peuna@ppshp.fi.
authors.forename: A
authors.initials: A
authors.lastname: Peuna
authors.affiliation: Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, Finland; Unit of Primary Health Care, Kuopio University Hospital, Kuopio, Finland. Electronic address: hannu.kautiainen@medcare.fi.
authors.forename: H
authors.initials: H
authors.lastname: Kautiainen
authors.affiliation: Mehiläinen Sports Medical Clinic, Jyväskylä, Finland. Electronic address: Harri.Selanne@likes.fi.
authors.forename: H
authors.initials: H
authors.lastname: Selänne
authors.affiliation: Department of Orthopaedics and Traumatology, University of Helsinki, and Helsinki University Hospital, Helsinki, Finland. Electronic address: ilkka.kiviranta@helsinki.fi.
authors.forename: I
authors.initials: I
authors.lastname: Kiviranta
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland. Electronic address: ari.o.heinonen@jyu.fi.
authors.forename: A
authors.initials: A
authors.lastname: Heinonen
mesh_terms: D002358:Cartilage, Articular; D005260:Female; D006801:Humans; D007719:Knee Joint; D008279:Magnetic Resonance Imaging; D020370:Osteoarthritis, Knee; D017698:Postmenopause; D055070:Resistance Training
keywords: Aquatic exercise; Cartilage; Magnetic resonance imaging (MRI); Osteoarthritis; Randomised controlled trial