Effectiveness of Distal and Proximal Muscle Fatigue for Healthy Young Adults

This is a study aiming to investigate the effects of acute muscle fatigue on muscle properties, balance and foot plantar pressure in healthy young adults (having no chronic diseases or orthopaedic diseases and physically active). This study also aims to compare the effects of foot muscle fatigue and hip muscle fatigue on balance and foot plantar pressure.

The exercises for ankle muscle fatigue are heel rise with bending your knee and heel raise without bending your knees.

The exercise for hip muscle fatigue is a single-leg squat. Before and after completing these all exercises, the balance is evaluated with an isokinetic balance device, the foot plantar pressure is evaluated with a pedobarography device and finally, the muscle properties are evaluated with a myotonPro device. All assessment devices are non-invasive.

The International Physical Activity Questionnaire (Short form) will be used to assess individuals' physical activity levels. Prior to the distal and proximal fatigue protocols, the participants' maximum isometric muscle forces of the gastrocnemius, soleus, tibialis anterior, rectus femoris, and gluteus maximus muscles will be evaluated using a dynamometer.

Then, the mechanical and viscoelastic properties of these muscles and the iliotibial band will be assessed using the MyotonPro device, participants' static foot pressure on both feet will be evaluated through pedobarography, and individuals' dynamic balance and static balance will be evaluated on one foot using the Technobody isokinetic balance device.

The individuals included in the study will undergo exercises targeting the foot plantar flexor and dorsiflexor muscles on the first day, and exercises targeting the hip flexor and extensor muscles on the second day. The researcher will measure the voluntary maximum isometric muscle strength using a dynamometer,

Heel raise exercises will be performed in 3 sets, with 30 seconds of free walking allowed for rest between sets. Individuals will initially complete 3 sets of this exercise without bending their knees. Then, they will perform the heel raise exercise with bent knees. The researcher will measure the voluntary maximum isometric muscle strength using a dynamometer when the Modified Borg Scale indicates a level of 7 or above. If the muscle strength has decreased to 50% of the initial force, indicating fatigue, the exercise will be terminated.

Second day, a single-leg squat will be performed in 3 sets, with 30 seconds of free walking allowed for rest between sets.The researcher will measure the voluntary maximum isometric muscle strength using a dynamometer when the Modified Borg Scale indicates a level of 7 or above. If the muscle strength has decreased to 50% of the initial force, indicating fatigue, the exercise will be terminated.

After the distal fatigue protocol, the viscoelastic properties of the gastrocnemius, soleus, and tibialis anterior muscles will be assessed using the MyotonPro device, while the plantar pressures will be evaluated through pedobarography. Additionally, static and dynamic balances will be measured using the Technobody device. Following the proximal fatigue protocol, the mechanical and viscoelastic properties of the gluteus maximus and rectus femoris muscles, along with the iliotibial band, will be examined using the MyotonPro device. Similarly, plantar pressures will be analyzed through pedobarography, and static and dynamic balances will be assessed using the Technobody device. The collected data will be recorded by the researcher.

Eligibility Criteria:
Inclusion Criteria:

* To be a healthy individual in the age range of 18-35,
* To be willing to participate in the study,
* To have a minimal active or highly active score on the International Physical Activity Questionnaire (Short Form),
* To have a body mass index (BMI) of 24.9 kg/m² or lower.

Exclusion Criteria:

* Having a history of injury and/or surgical operation related to the lower extremity,
* Having limited mobility in the lower extremity,
* Having any deformity related to the lower extremity,
* Having cardiovascular, vestibular, neurological, orthopedic, or skin-related diseases,
* Having any chronic disease that may affect balance,
* Having any acute/chronic musculoskeletal pain or systemic pain,
* Not to have given consent to participate in the study or to wish to withdraw from the study.