The study aims to investigate the effect of different Russian current parameters on maximum voluntary isometric contraction of the quadriceps muscle among University of Sharjah students.

Muscular strength and endurance are two important compatible parts of the body; for normal people to move, lift things and do day-to-day activities or athletic performance. Large number of studies have been carried out to elaborate the different factor that help in improving the muscular strength as well as the endurance combined with rehabilitation programs in order to promote muscle function and prevent the injury(Akinoglu & Kocahan, 2020; Chou & Binder-Macleod, 2007; Evetovich et al., 2001; Selkowitz, 1985; Snyder-Mackler et al., 1994; Ward et al., 2006). Strengthening and endurance training have been used frequently in varied rehabilitation protocols in order to improve the overall musculoskeletal performance.(Earl & Hoch, 2011; Gondin et al., 2011). Meanwhile, Isokinetic training and Neuromuscular electrical stimulation are frequently utilized in physical therapy.(Brown & Whitehurst, 2003; Chou & Binder-Macleod, 2007; Evetovich et al., 2001; Stone, 1997).

Russian current is one of the popular preferred Neuromuscular electrical stimulation as it has been advocated to increase muscle strength due to its high tolerance as well as minimum pain level provocation (Akinoglu & Kocahan, 2020; Gondin et al., 2011). Russian currents are alternating currents at a frequency of 2.5 kHz that are burst modulated at a frequency of 50 Hz with a 50% duty cycle. The widely and most popular training protocol used with Russian current is (10/50/10) in which the stimulus is applied for a 10-second "on" period followed by a 50-second "off" or rest period, with a recommended treatment time of 10 minutes per stimulation session. Russian currents are used mainly to generate a motor response, but it also has been investigated as an electro-analgesia type intervention. This training protocol is used mainly to generate a motor response, but it also has been investigated as an electro-analgesia type intervention.

Despite a lot of previous research regarding the Russian current; no studies are available in which suggest the most efficient carrier frequency for Russian current to strengthening the muscles and increase muscle with isokinetic training in the short term and the effect of different RC on the EIT by the quadriceps muscle. The aim of this study is directed toward investigation of those different Russian current carrier frequencies' effects on the quadriceps muscle isokinetic strength and endurance in addition to investigate the effect of different mode of RC on the EIT by the quadriceps femoris muscle. This study will include measurement for the knee torque and quadriceps muscle strength using Biodex system 3 that will be generated by different carrier frequency in addition to different RC mode, and investigate the relationship between those variables.

Inclusion Criteria:

1. Their age ranged from 18 to 25 years.
2. Their Body Mass Index (BMI) within normal range (18.5-25).
3. Don't have any health related condition that required medical attention in the past two years.
4. All participant at same physical fitness level.

Exclusion Criteria:

• The subjects will be excluded from this study if they have any of the following criteria:

  1. Quadriceps muscle injury.
  2. Spinal or lower limb fractures.
  3. Lower limb deformities.
  4. Associated cognition abnormalities which may to affect muscle and limb function
  5. Tumors or radicular symptoms
  6. Recent muscular lesion, knee injury, sensory changes and neuromuscular disease
  7. Previous surgery that may affect the lower limb muscle performance.
  8. Any contraindication for Russian current application

All information taken will be kept confidential and will not be taken without the participant's consent. Any data collected will be for scientific purpose only.The therapists have been instructed about the privacy, confidentiality and rights of the participants .

Published data will remain anonymous without personal identifier of participants