ALS Study Determining Various Biomarkers and Strength Comparison After Exercise

Inclusion Criteria: * Diagnosis of possible, probable or definite amyotrophic lateral sclerosis (ALS) based on the revised El-Escorial criteria * Presence in ipsilateral leg of either weakness in any muscle group or of active denervation by needle electromyography (EMG) which is a surrogate marker of early denervation * Ipsilateral quadriceps femoris strength: \>=4 * Ambulatory with or without assistance * Revised ALS Functional Rating Scale (ALSFRS-R) Score \> 30 * Forced expiratory vital capacity (FVC) \>50% of predicted Exclusion Criteria: * ALSFRS-R ≤ 30 * Quadriceps femoris strength \<4 * Unable to walk or uses wheelchair as primary means of mobility * More than mild atrophy of quadriceps * Bleeding disorder or uptake of anticoagulants * Unwilling to comply with exercise and needle muscle biopsy * Not a good research candidate according to the medical opinion of investigator