title: Effect of progressive high-impact exercise on femoral neck structural strength in postmenopausal women with mild knee osteoarthritis: a 12-month RCT.
abstract: It is uncertain whether subjects with mild knee osteoarthritis, and who may be at risk of osteoporosis, can exercise safely with the aim of improving hip bone strength. This RCT showed that participating in a high-impact exercise program improved femoral neck strength without any detrimental effects on knee cartilage composition.
  
  
  
  No previous studies have examined whether high-impact exercise can improve bone strength and articular cartilage quality in subjects with mild knee osteoarthritis. In this 12-month RCT, we assessed the effects of progressive high-impact exercise on femoral neck structural strength and biochemical composition of knee cartilage in postmenopausal women.
  
  
  
  Eighty postmenopausal women with mild knee radiographic osteoarthritis were randomly assigned into the exercise (n = 40) or control (n = 40) group. Femoral neck structural strength was assessed with dual-energy X-ray absorptiometry. The knee cartilage region exposed to exercise loading was measured by the quantitative MRI techniques of T2 mapping and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). Also, an accelerometer-based body movement monitor was used to evaluate the total physical activity loading on the changes of femoral neck strength in all participants. Training effects on the outcome variables were estimated by the bootstrap analysis of covariance.
  
  
  
  A significant between-group difference in femoral neck bending strength in favor of the trainees was observed after the 12-month intervention (4.4%, p < 0.01). The change in femoral neck bending strength remained significant after adjusting for baseline value, age, height, and body mass (4.0%, p = 0.020). In all participants, the change in bending strength was associated with the total physical activity loading (r = 0.29, p = 0.012). The exercise participation had no effect on knee cartilage composition.
  
  
  
  The high-impact training increased femoral neck strength without having any harmful effect on knee cartilage in women with mild knee osteoarthritis. These findings imply that progressive high-impact exercise is a feasible method in seeking to prevent hip fractures in postmenopausal women whose articular cartilage may also be frail.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Central Finland Central Hospital, Keskussairaalantie 19, 40620, Jyväskylä, Finland. juhani.multanen@ksshp.fi.|Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland. juhani.multanen@ksshp.fi.
authors.forename: J
authors.identifier: 0000-0003-0811-3504
authors.initials: J
authors.lastname: Multanen
authors.affiliation: Center for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University Melbourne, Melbourne, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Rantalainen
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.
authors.forename: H
authors.initials: H
authors.lastname: Kautiainen
authors.affiliation: Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.
authors.forename: R
authors.initials: R
authors.lastname: Ahola
authors.affiliation: Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.|Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.|Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Jämsä
authors.affiliation: Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.|Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.|Department of Radiology, University of Oulu, Oulu, Finland.
authors.forename: M T
authors.initials: MT
authors.lastname: Nieminen
authors.affiliation: Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.
authors.forename: E
authors.initials: E
authors.lastname: Lammentausta
authors.affiliation: Department of Physical Medicine and Rehabilitation, Central Finland Central Hospital, Keskussairaalantie 19, 40620, Jyväskylä, Finland.|Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Häkkinen
authors.affiliation: Department of Orthopaedics and Traumatology, University of Helsinki, and Helsinki University Hospital, Helsinki, Finland.
authors.forename: I
authors.initials: I
authors.lastname: Kiviranta
authors.affiliation: Department of Physical Medicine and Rehabilitation, Central Finland Central Hospital, Keskussairaalantie 19, 40620, Jyväskylä, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Heinonen
mesh_terms: D015502:Absorptiometry, Photon; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000503:physiopathology; D015444:Exercise / Q000502:physiology; D005081:Exercise Therapy / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D005272:Femur Neck / Q000503:physiopathology*; D006620:Hip Fractures / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications / Q000503:physiopathology / Q000534:rehabilitation*; D015663:Osteoporosis, Postmenopausal / Q000209:etiology / Q000517:prevention & control*; D058866:Osteoporotic Fractures / Q000209:etiology / Q000517:prevention & control; D016037:Single-Blind Method
keywords: Cartilage; Exercise; Menopause; RCT