Related Experiment Video
Updated: May 9, 2026
Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
Hamstring flexibility increases the same with 3 or 9 repetitions of stretching held for a total time of 90 s
A Wayne Johnson1, Ulrike H Mitchell1, Katie Meek1
1Brigham Young University, Dept. of Exercise Sciences, Provo, UT 84602, USA.
Objective:
To determine if stretching for a constant total time with differing repetition durations and number of repetitions over a 6-week period produced different changes in hamstring flexibility measured by knee extension range of motion (ROM).
Design:
Randomized Control Trial.
Setting:
University laboratory.
Subjects:
34 volunteers, 18-25 years old with tight hamstrings as determined by a greater than 30° loss of knee extension with hip flexed to 90° participated in the study.
Main Outcome Measures:
Change in knee extension ROM was assessed in participants who were randomly assigned to a control, or to a stretching group of either 10 s for 9 repetitions or 30 s for 3 repetitions, for a total stretch time of 90 s. Each group stretched 6 days a week for 6 weeks.
Results:
Pre to post stretch comparison indicated both stretching groups were successful in increasing joint ROM (11.6 ± 5.25°-13.4 ± 5.36°) over the control (F = 19.77, p < 0.003). However, there was no significant difference between the stretching groups (p = 0.9).
Conclusion:
Stretching for 6 weeks for total of 90 s showed increased joint ROM regardless of the number of repetitions or the duration of each individual stretch.
More Related Videos
08:48Adapted Resistance Training Improves Strength in Eight Weeks in Individuals with Multiple Sclerosis
Published on: January 29, 2016
08:40Isokinetic Robotic Device to Improve Test-Retest and Inter-Rater Reliability for Stretch Reflex Measurements in Stroke Patients with Spasticity
Published on: June 12, 2019
Related Concept Videos
01:23Muscles that Move the Leg
Anterior Compartment
The quadriceps femoris, the most visible muscle of the anterior compartment, is integral for leg extension and thigh flexion. It is formed by merging four distinct muscles — the vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris. The quadriceps tendon, a shared tendon of the four quadriceps muscles, is affixed to...
01:22Muscle Stimulation Frequency
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
01:27Exercise and Muscle Performance
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
01:29Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
01:22Somatic Spinal Reflexes
One of the most well-known somatic spinal reflexes is the stretch reflex, which is activated by the sudden stretching of a muscle. This reflex involves the activation of specialized sensory receptors called muscle spindles, which are located in the muscle tissue and detect changes in the length and speed of muscle contractions. When a muscle is suddenly...