First, it is important to keep in mind that the project will focus largely on mobile usability, particularly tablets, and that the designs below focus on the problem of coaches having an efficient means to record and recall player performances.
Design 1:
The first design focuses on simplicity, chunking, and feedback. Additionally this design is robust to different training routines.
The user selects the player, routine, and date using the sliders and calendar selector on the top. The user then inputs performances for that routine and gets feedback about how that player has been trending as well as recent performances.
Design 2:
The second design focuses on efficiency. Some robustness is sacrificed as the UI is more tailored toward fast recording the performances of a number of players in a team. The user selects the date and routine at the top of the screen (another selector, such as 'Player Group' could be added). The first and second columns of the main UI list player numbers and names. The third column displays a range of likely values for player performances based on previous performances, so that to record a particular performance the user (a coach) need only tap the screen once.. The range is horizontally slide-able, and a 'long press' can pull up a touch-screen keyboard for text input, in the case that the value is outside the desired range. The last recorded value per player is faintly highlighted and their performance for this routine/day (if recorded) is boldly highlighted.
For continuous-domain performance recording, a slider is used instead of the selector above per row.
Design 3:
This design focuses on being robust and information rich. It is lightly metaphorical in that it takes after an actual clipboard.
The user selects the routine/date at the top of the screen, and the scores for all players for that routine/day are displayed. Scrolling (sliding) vertically shows information for different players and sliding horizontally shows information for different exercises (if there are too many to display). The user can then on one screen edit information for any player and for any exercise by pressing on a table entry, which brings up a quick interface for selecting the desired value. A double tap will allow standard text input via a pop-up number pad.
The default interface is a slider with values displayed in a likely range and the slider initially set to the last recorded value for that player/exercise, but the exact interface will depend on what is being recorded--for instance, if recording a time, a clock-based selector would appear.
Tabs on the bottom allow the user to navigate to other screens, to add players, set up routines, view results, etc.
For safety, the table is only editable by default if its date is the current day.
The primary focus of these designs overall is on efficiency of input.