Descriptive Study of Strength Training Exercises to Activate the Muscles of the Operated Leg After Total Knee Replacement
Condition: Osteoarthritis, Knee
MeSH terms: Osteoarthritis, Knee
Study type: Interventional
Phase: Phase 1

Summary: 
      Background:

      In the early phase after a total knee replacement (TKA), patients experience multi-level
      weakness in the operated leg, which is caused primarily by reduced central (CNS) activation
      failure of the muscles - especially the knee extensors. This considerable loss of muscle
      strength relates to reduced functional performance. The investigators recently reported that
      early-commenced physiotherapy, including progressive strength training performed in machines,
      seems feasible after TKA. The question is, if neuromuscular activity of the muscles in the
      operated leg, elicited during strength training in machines, can be reached during strength
      training in more simple forms? Many clinicians are faced with the problem of not having
      strength training equipment at their institution, or having to prescribe simple strength
      training exercises for home-based training.

      Purpose and hypothesis:

      The purpose of this study is to determine which strength training exercises that activate the
      muscles in the operated leg the most after TKA. The hypothesis is that strength training
      exercises performed in machines is more effective compared to strength training performed in
      more simple forms (using elastic bands or own body weight, etc.).

      Participants and methods:

      Twenty participants with a unilateral TKA, operated between 4 to 8 weeks prior to the first
      investigation, will be included. The participants are investigated twice. During the first
      investigation, the absolute load (kilograms) corresponding to 10 Repetition Maximum (RM) (a
      load that can be lifted exactly 10 times) will be determined for all the exercises. At least
      72 hours later, the participants will undergo an electromyographic analysis, which determines
      the neuromuscular activity of the thigh muscles in the operated leg.

      Ethical issues:

      From a pilot study, the investigators found that strength training exercises commenced early
      after TKA seems feasible as the exercises did not increase knee joint swelling or knee pain.
      None of the financial supporters, or any of the authors, have any potential conflicts of
      interest with regard to the study.
    


Intervention name(s): Six different strength training exercises
Intervention type(s): Other
Intervention description(s): Electromyographic (EMG) activity of the vastus medialis, vastus lateralis, semitendinosus and biceps femoris muscles of the operated leg will be recorded during 6 different strength training exercises. The six exercises performed unilaterally are: seated knee extensions and leg presses in machines (gold standard exercises), and the four other exercises are: sit-to-stands, squats, straight leg raises and seated knee extensions using an elastic band.
The relative loading will be 10 repetition maximum (RM). The absolute load (kilograms) corresponding to 10 RM of the 6 strength training exercises is defined a minimum of 3 days before the day where the EMG-data are recorded. Range of motion and time under tension for each repetition will be controlled for.
Other intervention name(s): Resistance training
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Arthroplasty, Replacement, Knee; Electromyography; Resistance training; Physical Therapy Modalities