This study aimed to clarify the contribution of the dorsal interosseus (DI) muscles to proximal interphalangeal (PIP) joint extension function. Six healthy males were included in the study. PIP joint extension angle and torque were measured upon electrical stimulation of the 2^nd and 3^rd DI muscles; furthermore, an electromyogram of both muscles during active maximum PIP joint extension was obtained. Six positions were measured between metacarpophalangeal (MP) joint flexion of 80° and hyperextension (MPH) of 20° (MP80, MP60, MP40, MP20, MP0, and MPH20).

The average PIP joint extension angle upon electrical stimulation of the 2^nd DI muscle was almost constant within −60° to −70° regardless of MP joint position. Although it was 0° for MP40 and MP20 upon stimulation of the 3^rd DI muscle, it was around −30° and −50° for MPH20 and MP80, respectively (p < 0.01). PIP joint extension torque was measured at MP40 and MP20, where full extension was possible, and 0.03 Nm at MP40 and 0.05 Nm at MP20. Muscular activity during finger extension motion by the maximum effort was approximately 30% of the maximum activity at MP40 and approximately 70% at MP80 and MPH20 as a peak value for both muscles (p < 0.01).

This study revealed that the 3^rd DI muscle governs PIP joint extension function; its degree of effect is influenced by MP joint position. Moreover, muscular activity in PIP joint extension motion fluctuates with MP joint position, and the muscles are activated at positions where PIP joint extension is not efficiently obtained. This increased activity is caused by suppression of MP joint extension, which increases the PIP joint extension function via the extensor digitorum muscles.

We examined the American football coaches' ability to perceive various situations such as alignments, formations, performances, and tactical anticipation during a game. This study investigated the differences in cognition among three coaches at different levels of proficiency (beginner, less experienced, and experienced), by using the “ongoing” cognitive method. This method recorded what and where the coaches observed during a game. Coaches were requested to state their observations while watching these game videos. Data were collected three times to (1) examine the effectiveness of the ongoing method, and (2) determine whether it contributed to improving their coaching skills. Results revealed that the more experienced a coach was, the more he/she recognized better. Their situated cognition improved with the repetition of the ongoing cognitive method as well.

Electrophysiological recordings of eye movement are important for the discipline of orthoptics not only in clinical evaluation of visual function but also for understanding the properties of visuomotor coordination. Therefore, low-cost visual stimulators with real-time output of current stimulation status are required for effective student practice. In this report, three types of stimulators were tested for recording saccadic and pursuit eye movements and optokinetic nystagmus in electrooculography practice. These stimulators were built with low-cost, general-purpose parts and might improve the student training courses for certified orthoptists, a specialty that requires thorough knowledge of the complex properties of various human eye movements.