Core Concepts

openweight models strength training using a hierarchy of concepts that map to how athletes think about their training.

Data Hierarchy

Program
└── ProgramWeek[]
    └── WorkoutTemplate[]
        └── ExerciseTemplate[]
            └── SetTemplate[]

WorkoutLog (completed session)
└── ExerciseLog[]
    └── SetLog[]

Completed vs. Planned

openweight distinguishes between what you plan to do and what you actually did:

Planned (Templates)	Completed (Logs)
WorkoutTemplate	WorkoutLog
ExerciseTemplate	ExerciseLog
SetTemplate	SetLog
targetReps, targetWeight	reps, weight

A WorkoutLog can reference the template it was created from via templateId.

Exercise

An Exercise describes which movement was performed:

Field	Type	Description
name	string	Human-readable name (required)
equipment	string	Equipment used: barbell, dumbbell, bodyweight, etc.
category	string	Body part: chest, back, legs, etc.
musclesWorked	string[]	Specific muscles targeted

The same Exercise definition is shared between logs and templates.

Sets

SetLog (Completed)

Records what actually happened in a set:

Field	Type	Description
reps	integer	Repetitions completed
weight	number	Weight used
unit	"kg" | "lb"	Weight unit (required if weight is present)
durationSeconds	integer	Time for timed exercises
rpe	number (0-10)	Rate of Perceived Exertion
rir	integer	Reps In Reserve
toFailure	boolean	Whether the set was taken to failure
type	string	Set type: working, warmup, dropset, etc.
tempo	string	Tempo notation (e.g., "3-1-2-0")

SetTemplate (Planned)

Prescribes what to do in a set:

Field	Type	Description
targetReps	integer	Target rep count
targetRepsMin / targetRepsMax	integer	Rep range (e.g., 8-12)
targetWeight	number	Absolute weight target
percentage / percentageOf	number/string	Percentage-based (e.g., 80% of 1RM)
targetRPE	number	Target RPE
targetRIR	integer	Target RIR

Units

Weight Units

Value	Description
kg	Kilograms
lb	Pounds

Rule: If weight is present, unit is required.

Distance Units

Value	Description
m	Meters
km	Kilometers
ft	Feet
mi	Miles
yd	Yards

Rule: If distance is present, distanceUnit is required.

Intensity Metrics

RPE (Rate of Perceived Exertion)

A 0-10 scale measuring how hard a set felt:

RPE	Description
10	Maximum effort, no reps left
9	Could do 1 more rep
8	Could do 2 more reps
7	Could do 3 more reps

Decimals are allowed (e.g., 8.5).

RIR (Reps In Reserve)

An alternative to RPE, counting reps left in the tank:

RIR	Description
0	No reps left (failure)
1	1 rep left
2	2 reps left

Tempo Notation

Tempo is expressed as four numbers: eccentric-pause-concentric-pause

Notation	Description
3-1-2-0	3s down, 1s pause, 2s up, no pause at top
4-0-1-0	4s down, no pause, 1s up, no pause
2-0-X-0	2s down, no pause, explosive up, no pause

Use X for explosive (as fast as possible).

Supersets

Exercises can be grouped into supersets using supersetId:

{
  "exercises": [
    {
      "exercise": {
        "name": "Bench Press"
      },
      "supersetId": 1,
      "sets": [
        ...
      ]
    },
    {
      "exercise": {
        "name": "Bent Over Row"
      },
      "supersetId": 1,
      "sets": [
        ...
      ]
    }
  ]
}

Exercises with the same supersetId are performed together.

Extensibility

All openweight objects allow additional properties. Apps can store custom data using a namespaced key:

{
  "date": "2024-01-15T09:30:00Z",
  "exercises": [
    ...
  ],
  "myapp:sessionId": "abc123",
  "myapp:gymLocation": "Downtown"
}

Use a prefix like myapp: to avoid conflicts with future schema fields.