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Descriptive Study of Strength Training Exercises to Activate the Muscles of the Operated Leg After Total Knee Replacement

This study has been completed.
Information provided by (Responsible Party):
Thomas Linding Jakobsen, Copenhagen University Hospital, Hvidovre Identifier:
First received: October 16, 2012
Last updated: October 22, 2013
Last verified: October 2013


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.

Condition Intervention Phase
Osteoarthritis, Knee
Other: Six different strength training exercises
Phase 1

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Neuromuscular Activity of the Operated Leg During Strength Training Performed in Machines and in More Simple Forms After Total Knee Replacement

Resource links provided by NLM:

Further study details as provided by Copenhagen University Hospital, Hvidovre:

Primary Outcome Measures:
  • Normalized neuromuscular activity (EMG) of the quadriceps and hamstring muscles [ Time Frame: One time point, 4 to 8 weeks after TKA ]
    Normalized electromyographic (EMG) activity (amplitude) during the different exercises. The EMG activity elicited during standardized, maximal contractions is used as a reference for normalization.

Enrollment: 24
Study Start Date: October 2012
Study Completion Date: February 2013
Primary Completion Date: February 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Six different strength training exercises
Six different strength training exercises are investigated. Four repetitions of each exercise are performed with a relative loading of 10 RM.
Other: Six different strength training exercises

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 Name: Resistance training


Ages Eligible for Study:   18 Years to 80 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Unilateral primary TKA
  • Between the age of 18 to 80 years
  • Understand and speak Danish
  • Informed consent
  • 4 to 8 weeks after TKA

Exclusion Criteria:

  • Disease/Musculoskeletal disorder, which requires a special rehabilitation modality
  • Alcohol and drug abuse
  • Lack of wish to participate or unwillingness to sign an informed consent
  Contacts and Locations
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Please refer to this study by its identifier: NCT01708980

Clinical Research Centre, Copenhagen University Hospital, Hvidovre
Hvidovre, Copenhagen, Denmark, 2650
Sponsors and Collaborators
Copenhagen University Hospital, Hvidovre
Study Director: Thomas Bandholm, PhD Clinical Research Center, Copenhagen University Hospital, Hvidovre, Denmark
  More Information

Responsible Party: Thomas Linding Jakobsen, Research Physiotherapist, Copenhagen University Hospital, Hvidovre Identifier: NCT01708980     History of Changes
Other Study ID Numbers: 2012-09-TLJ
Study First Received: October 16, 2012
Last Updated: October 22, 2013

Keywords provided by Copenhagen University Hospital, Hvidovre:
Arthroplasty, Replacement, Knee
Resistance training
Physical Therapy Modalities

Additional relevant MeSH terms:
Osteoarthritis, Knee
Joint Diseases
Musculoskeletal Diseases
Rheumatic Diseases processed this record on April 26, 2017