The study will contribute to answering the question of 'in which exercise types of single-leg and double-leg exercise protocols will affect whether fatigue occurs early or not, and muscle activations will occur. In response to this question, clinicians will prefer to focus on which type of exercise produces more muscle activation and late fatigue. Few studies have been done on single and double leg bicycle ergometers in the literature. From these studies; While examining the lactate and EMG threshold values after cycling ergometer training, another study compared the effectiveness of single and double leg cycling ergometers. In the literature, EMG and dynamic balance were not used in the comparison after single and double leg bicycle ergometer training. In this study, the effectiveness of single and double legged bicycle ergometers will be compared by looking at EMG and dynamic balance changes.

In humans, one side of the body is often preferred over the other to perform voluntary motor actions. There is evidence that in bipedal cycling training, where both legs are simultaneously involved in the motor task, the dominant leg contributes more to the power produced than the non-dominant leg. The magnitude of asymmetries between both legs can vary (eg 1-40%) and depend on the variable of interest (eg power, torque, etc.), pedaling phase, intensity and cadence. Bicycle ergometer leg exercise has been applied in the literature as an assessment tool for motor function, aerobic training method and also for individuals. Cycling performance depends on the optimization of physiological, psychological and biomechanical parameters. There are already many studies on physiological or psychological performance parameters. The pedaling paradigm has many advantages. It minimizes postural control, is characterized by a restricted kinematic trajectory, requires less effort for training control, and shares a similar muscle activation pattern with walking. EMG is an indirect measure of muscle activity as it detects the electrical activity produced by the passage of a nerve impulse that causes an action potential in the muscle cell membrane. This potential consists of three phases: membrane depolarization, repolarization, and hyperpolarization period, which produces an electric field picked up by the EMG electrodes. Decomposition techniques have been applied to EMG signals to identify motor patterns of joint activation between muscle groups, called motor modules or muscle synergies. Each synergy is represented by a spatial component that reflects the composition of muscle co-activation and a temporal component that elicits modulus uptake throughout the execution of the movement. Successfully applied to different motor behaviors, this analysis supports the hypothesis of a low-dimensional modular organization at the central nervous system level. Muscle electrical activity is measured using electromyography (EMG). The amplitude of the EMG signal has a monotonic relationship with the number of activated muscle fibers and is therefore a good indicator of contraction intensity. In dynamic studies, the signals reaching the motor unit, which can be detected at the location of the electrode, overlap electrically and are observed as a bipolar signal with symmetrical negative and positive amplitude distribution. The signal obtained without filtering is called the "Raw signal", which consists of periods of contraction and relaxation. During the rest period, the baseline EMG is observed, which depends on many factors (quality of the amplifier, environmental noise, and the quality of the given sensing condition) and should not exceed line 3 if these factors are within appropriate limits. 5 microvolts (mV). During normal bipedal bicycle pedaling, when the leg extensor muscles are active during the first half of the 360̊ crank cycle, crank torque is mainly produced in the down phase of each leg while pedaling. For training and rehabilitation purposes, they sometimes engage in 1-leg pedaling with crank torque produced by only one leg, emphasizing the need for ipsilateral flexor activity in the upward movement of the foot to produce crank torque while pedaling and produce a smooth pedaling motion throughout. the entire crank cycle. Therefore, single-leg pedaling requires cyclists to change how they control. multiple extensor and flexor leg muscles during the crank cycle. Therefore, the 1-leg bike has been proposed as a training tool to improve pedaling performance and is used in clinical settings for rehabilitation. EMG studies with bicycle ergometer are insufficient in the literature. During this activity, there is no study in the literature comparing single-leg and double-leg exercises during single-leg cycling exercise, which is frequently used to prevent premature fatigue in leg muscles in chronic obstructive pulmonary patients. Although ergometer exercise is frequently used in rehabilitation treatment, it increases maximum oxygen uptake and muscle strength, decreases systolic and diastolic blood pressures, decreases body weight and body fat, improves cognitive function, balance function and muscle activity in the literature is limited. This study will contribute to answering this question that the exercise types of single-leg and double-leg exercise protocols will affect whether muscle activations occur early or not. In response to this question, clinicians will prefer to focus on which type of exercise produces more muscle activation and late fatigue. There have been a few studies in the literature on single and double leg bicycle ergometers. From these studies; Looking at the lactate and EMG threshold values after cycling ergometer training, another study compared the effectiveness of a single ergometer.

Inclusion Criteria:

• Volunteering to participate in the study
• Absence of comorbid disease of orthopedic, neurological, cardiopulmonary system
• Participants who have not participated in another clinical trial in the last 1 month
• Participants with a Body Mass Index (BMI) below 30 kg/m2

Exclusion Criteria:

• Participants who had hip, pelvis, knee, ankle surgery in the last year
• Participants with leg length inequality
• Those with known balance disorders in the last three months due to vestibular disorders, pregnancy, concussion participants
• Participants taking any medication that may affect alertness or balance.
• During the study protocol, the participants did not comply with the requested requests.
• Presence of peripheral nerve dysfunctions and neurological disorders
• Presence of a previous injury to the feet or legs
• Prior surgery on the lower extremities
• Systemic discomfort
• Pain and other medical conditions that may affect postural control

Healthy adult