Electromyography (EMG), the methodology to record muscle activity, has been unchanged for many years, with the use of instrumentation amplifiers (IAs). To overcome limitations of IAs when measuring EMG activity from pennate muscles, a transimpedance amplifier (TIA) has been proposed [1]. The TIA has the advantage of conserving all frequency information in the EMG signal. However, there are some limitations of the originally proposed current-amplifier. In this thesis, we present the design and development of an improved current-amplifier. Additionally, an isolation module was developed to record from multiple muscles simultaneously. The new current-amplifier was used in two experiments. The first experiment was conducted to test coherence, a metric that determines similarity in the frequency content of two signals, as an indicator of fatigue during a dynamic activity. The second experiment was conducted to test the ability of a biofeedback system to modulate coherence.