**3. Smartphone: wireless gyroscope platform for quantifying human movement**

With the continuous evolution of the smartphone eventually the gyroscope was integrated into the inertial sensor package. The gyroscope measures the rate of angular rotation, which offers a readily clinically identifiable metric, especially in consideration of the orientation of a particular joint [1–3, 22]. In particular the smartphone as a wireless gyroscope platform can quantify the characteristics of the patellar tendon reflex response [31].

In order to accurately and consistently quantify the reflex response of the patellar tendon through the application of a smartphone as a wireless gyroscope platform, a means of evoking the reflex with a similar level of accuracy and consistency is imperative. The potential energy impact pendulum attached to a reflex hammer was selected, which has been successfully researched, developed, tested, and evaluated, while demonstrating the ability to elicit the tendon reflex at prescribed levels of potential energy with predetermined targeting [14–19]. The integration of the potential energy impact pendulum and smartphone as a wireless gyroscope platform provide considerable opportunity for the accurate and consistent measurement of the reflex response.

The reflexes of the lower limb are synergistically interrelated with the function of gait [19]. Therefore with the success of the smartphone as a wireless accelerometer platform for quantifying gait, the patellar tendon reflex response logically should also be a readily quantifiable aspect of human movement. Preliminary testing and evaluation the smartphone as a wireless accelerometer for quantifying reflex response pertained to manual stimulation of the patellar tendon reflex [27]. The accurate and consistent quantification of the patellar tendon reflex can be further facilitated through the application of a potential energy impact pendulum for evoking the tendon reflex response with a prescribed amount of energy that is also targeted

Using a remote and effectively rural area as an experimental site, LeMoyne and Mastroianni applied a smartphone as a wireless accelerometer platform in conjunction with a potential energy impact pendulum. The integration of these devices readily acquired a recording of the reflex response acceleration waveform for the patellar tendon. The trial data was conveyed by wireless transmission to the Internet as an email attachment. Remotely situated post-processing resources applied software automation to quickly determine the efficacy of the experimental trial data. The findings advocate that the patellar tendon reflex response can be readily acquired through the integral application of the potential energy impact pendulum with the smartphone as a wireless accelerometer platform in an accurate and consistent manner [28]. Further establishment of the smartphone for quantifying the reflex response was

Further investigation of the opportunities for gait quantification emphasized the evaluation of gait for people with transtibial amputation. In consideration of people with transtibial amputation, they require a different mounting technique as opposed to merely applying an elastic band to secure the smartphone. In order to resolve this matter, a 3D printed mounting adapter was applied to secure the smartphone to the transtibial prosthesis. The smartphone conveniently measured the acceleration waveform of the subject's gait respective of the transtibial prosthesis. Automated software facilitated the post-processing endeavor with gait character-

**3. Smartphone: wireless gyroscope platform for quantifying human** 

With the continuous evolution of the smartphone eventually the gyroscope was integrated into the inertial sensor package. The gyroscope measures the rate of angular rotation, which offers a readily clinically identifiable metric, especially in consideration of the orientation of a particular joint [1–3, 22]. In particular the smartphone as a wireless gyroscope platform can

In order to accurately and consistently quantify the reflex response of the patellar tendon through the application of a smartphone as a wireless gyroscope platform, a means of evoking the reflex with a similar level of accuracy and consistency is imperative. The potential energy impact pendulum attached to a reflex hammer was selected, which has been successfully researched,

to a specified aspect of the patellar tendon [14–19].

4 Smartphones from an Applied Research Perspective

demonstrated though the application of an artificial reflex system [29].

quantify the characteristics of the patellar tendon reflex response [31].

istics acquired in an accurate and reliable manner [30].

**movement**

Upon the experimentation trial data was conveyed by wireless transmission to the Internet as an email attachment. Each gyroscope signal was post-processed through a software automation program for the acquisition of a pertinent parameter, such as the maximum gyroscope signal of the response. This preliminary investigation of the application of the smartphone as a wireless gyroscope platform in conjunction with a potential energy impact pendulum demonstrated the ability to accurately and reliability quantify the patellar tendon reflex response in terms of the gyroscope signal [31].

Further testing and evaluation of the smartphone as a wireless gyroscope platform investigated the capability to quantify gait. Using a mounting strategy that positioned the smartphone about the trunk, preliminary gyroscope signal data was acquired for gait. The findings implied that the smartphone as a wireless gyroscope platform could also be applied for identifying gait characteristics [32].

Later in the chapter the expanded role of the smartphone as a wireless gyroscope platform is demonstrated for the domain of machine learning classification. An assortment of machine learning algorithms are applied, for which the gyroscope signal provides a suitable feature set. Machine learning using the smartphone as a wireless gyroscope emphasizes the domains of classifying therapy exercise status and differentiating hemiplegic affected and unaffected reflex pairs.

The portable media device represents a similar wireless sensor platform, first with the accelerometer and later with the gyroscope. The portable media device and smartphone are supported by the same software application, such as for the iPod and iPhone. The appropriateness of either device for an experiment quantifying human movement is at the discretion of the research team. For example, the portable media device has a reduced telecommunications footprint, which is restricted to local wireless connectivity for access to the Internet; however the portable media device in general is somewhat lighter and relatively cheaper [1–3]. The following section investigates the capability of the portable media device of quantifying human movement, such as reflex and gait, first from the perspective of a wireless accelerometer platform.
