Effects of Adding End-Range Isometric Holds to Isotonic Knee Extensor Training on Isokinetic Performance in Sedentary Adults
Effects of Adding End-Range Isometric Holds to Isotonic Knee Extensor Training on Isokinetic Performance in Sedentary Adults: A Randomized Controlled Trial
The goal of this clinical trial is to learn if adding a short muscle hold (isometric contraction) to a standard leg-strengthening exercise improves knee muscle strength more than the standard exercise alone, in healthy adults who do not exercise regularly. The main question it aims to answer is:
Does adding a 5-second hold at the end of each leg-extension exercise lead to greater gains in front-thigh muscle (quadriceps) strength than leg-extension exercise alone?
Researchers will compare two exercise groups to see if the added muscle hold makes a difference:
Group 1 will do leg-extension exercises with a 5-second hold added at the end of each repetition.
Group 2 will do the same leg-extension exercises without the added hold.
Participants will:
Do leg-extension exercises 3 days a week for 8 weeks Have their thigh muscle strength tested before and after the program using a special exercise machine Have their thigh size measured before and after the program
Studie Overzicht
Toestand
Conditie
Interventie / Behandeling
Gedetailleerde beschrijving
Quadriceps femoris weakness is associated with several musculoskeletal conditions, including knee osteoarthritis, and is a common target of physiotherapy strengthening protocols. While isotonic and isokinetic strengthening methods have each been studied separately, it remains unclear whether adding an isometric hold to isotonic exercise provides additional benefit in isokinetic strength outcomes. This study addressed that question.
This was a randomized, two-arm study conducted at the Sportomed Sports Health and Orthopedic Rehabilitation Clinic (December 2014-May 2015). Forty-six sedentary, healthy adults aged 18-40 years were enrolled, with 43 completing the 8-week protocol. Exclusion criteria included lower-extremity musculoskeletal problems, prior lower-extremity surgery or significant trauma, low back pain, cardiac or neurological conditions, and chronic systemic disease. The study was approved by the Istanbul Medipol University Non-Interventional Clinical Research Ethics Committee (decision no. 257, 07.11.2014), and written informed consent was obtained from all participants.
Participants were randomized to two groups. Both performed isotonic knee-extension exercise (2 sets × 10 repetitions, 60% of 1RM) 3 days/week for 8 weeks, with weekly load progression (~5%) and 60 seconds rest between sets. Group 1 (n=21) added a 5-second isometric hold at 0° knee extension at the end of each repetition; Group 2 (n=22) performed the isotonic protocol without this addition.
Outcomes were assessed at baseline and after 8 weeks: thigh circumference, 1RM isotonic quadriceps strength, and isokinetic peak torque (PT, Nm) at 60°/second and 180°/second using a CSMI Humac Norm 2004 dynamometer. Baseline assessments also included range of motion, manual muscle testing, and physical activity level (IPAQ Short Form).
Statistical analysis was performed using NCSS 2007. Normality was assessed with Shapiro-Wilk testing. Between-group comparisons used independent t-tests or Mann-Whitney U tests as appropriate; within-group pre-post comparisons used paired t-tests. Categorical variables were compared using chi-square testing, and correlations using Pearson testing. Significance was set at p<0.05.
Studietype
Inschrijving (Werkelijk)
Fase
- Niet toepasbaar
Contacten en locaties
Studie Locaties
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Bostancı/Kadıköy
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Istanbul, Bostancı/Kadıköy, Turkije (Türkiye), 34744
- Sportomed | Physical Therapy and Rehabilitation Center
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Deelname Criteria
Geschiktheidscriteria
Leeftijden die in aanmerking komen voor studie
- Volwassen
Accepteert gezonde vrijwilligers
Beschrijving
Inclusion Criteria:
- Age 18-40 years
- Sedentary lifestyle (low physical activity level)
- Healthy individuals with no known knee-related disability
Exclusion Criteria:
- Musculoskeletal problems of the lower extremity
- History of lower extremity surgery or significant trauma
- Low back pain and/or lumbar region problems
- Cardiac complaints
- Neurological complaints
- Chronic systemic disease (e.g., diabetes mellitus, rheumatologic conditions)
Studie plan
Hoe is de studie opgezet?
Ontwerpdetails
- Primair doel: Behandeling
- Toewijzing: Gerandomiseerd
- Interventioneel model: Parallelle opdracht
- Masker: Enkel
Wapens en interventies
Deelnemersgroep / Arm |
Interventie / Behandeling |
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Experimenteel: Isotonic + Isometric Hold Group
Participants performed isotonic knee-extension exercise (2 sets of 10 repetitions at 60% of 1-repetition maximum) using a leg-extension machine, 3 days per week for 8 weeks, with weekly load progression (~5%) and 60 seconds of rest between sets.
At the end of each repetition, participants held the lifted weight for 5 seconds at 0° knee extension (isometric contraction) before returning to the starting position.
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Isotonic knee-extension exercise (2 sets of 10 repetitions at 60% of 1-repetition maximum) performed 3 days per week for 8 weeks, with weekly load progression (~5%) and 60 seconds of rest between sets.
Each repetition concluded with a 5-second isometric hold of the lifted weight at 0° knee extension.
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Actieve vergelijker: Isotonic Only Group
Participants performed the same isotonic knee-extension exercise protocol (2 sets of 10 repetitions at 60% of 1-repetition maximum) using a leg-extension machine, 3 days per week for 8 weeks, with weekly load progression (~5%) and 60 seconds of rest between sets, without the addition of an isometric hold at the end of each repetition.
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Isotonic knee-extension exercise (2 sets of 10 repetitions at 60% of 1-repetition maximum) performed 3 days per week for 8 weeks, with weekly load progression (~5%) and 60 seconds of rest between sets, without an added isometric hold.
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Wat meet het onderzoek?
Primaire uitkomstmaten
Uitkomstmaat |
Maatregel Beschrijving |
Tijdsspanne |
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Change in Quadriceps Femoris Isokinetic Peak Torque
Tijdsspanne: Baseline and 8 weeks
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Quadriceps femoris isokinetic peak torque (PT, Nm) was measured bilaterally using a CSMI Humac Norm 2004 isokinetic dynamometer at angular velocities of 60°/second (5 maximal repetitions) and 180°/second (15 maximal repetitions).
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Baseline and 8 weeks
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Secundaire uitkomstmaten
Uitkomstmaat |
Maatregel Beschrijving |
Tijdsspanne |
|---|---|---|
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Change in Quadriceps Femoris 1-Repetition Maximum (1RM) Isotonic Strength
Tijdsspanne: Baseline and 8 weeks
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Quadriceps femoris 1-repetition maximum isotonic strength was measured bilaterally using a leg-extension apparatus, with each disk increment corresponding to 10 lbs (4.54 kg).
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Baseline and 8 weeks
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Change in Thigh Circumference
Tijdsspanne: Baseline and 8 weeks
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Thigh circumference was measured bilaterally, 15 cm proximal to the superior border of the patella, using a measuring tape, in the supine position.
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Baseline and 8 weeks
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Medewerkers en onderzoekers
Sponsor
Onderzoekers
- Studie directeur: Feyza Şule Hantal, PhD, Yeditepe University
Studie record data
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Studie start (Werkelijk)
Primaire voltooiing (Werkelijk)
Studie voltooiing (Werkelijk)
Studieregistratiedata
Eerst ingediend
Eerst ingediend dat voldeed aan de QC-criteria
Eerst geplaatst (Werkelijk)
Updates van studierecords
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Meer informatie
Termen gerelateerd aan deze studie
Trefwoorden
Andere studie-ID-nummers
- 127742
Informatie over medicijnen en apparaten, studiedocumenten
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