Fitness

Train your Run skill on a deer-hide treadmill, but pace yourself: overworked running muscles cost more stamina.

Watch the 42-second gameplay showcase: Meadows, Black Forest, Swamp, Mountains, Plains and Mistlands.

Core features

• Buildable wooden treadmill with a moving deer-hide belt. Train Run in place at 1.5× normal XP by default.
• Three muscle-strain levels from sustained sprinting: mild +15%, moderate +30%, severe +50% running stamina drain. Other stamina costs are unchanged.
• Skill-based endurance: higher Run skill slows strain buildup; at Run 75, no new strain accumulates by default.
• Run–walk training: exhaustion switches to walking in place; running resumes automatically when native stamina fills. Recovery walking grants no Run XP and lets strain heal.
• Harder treadmill workouts: running on the treadmill builds strain 2× faster than ordinary sprinting by default; walking recovery is unchanged.
• Separate treadmill XP, stamina-cost and strain-buildup multipliers.

Build and use

Use Hammer → Furniture → Treadmill, near a workbench, with:

Interact to start or stop training. Move or jump to dismount in either phase. Exhaustion keeps you on the treadmill, walking until stamina reaches its current maximum, then automatically running again. Only the running phase consumes running stamina, grants Run XP and builds strain. Walking uses native regeneration, with no stamina grants or refunds.

You can open inventory during either phase; the workout continues. Other blocking interfaces, damage, death, teleporting or destruction of the treadmill end the session.

Only sprinting builds muscle strain, including treadmill running. At a fixed Run skill of 0, the default is 60 cumulative sprint seconds per strain level; Run 30 takes 100 seconds and Run 50 takes 180 seconds, before accounting for recovery. At Run 75+, no new strain builds by default. Walking or resting while alive heals one load unit per 600 seconds, including treadmill recovery walking. Short breaks retain unrecovered fatigue; stopping does not immediately clear an injury. Death, teleporting and time offline do not heal strain.

Configuration

Launch once, then close Valheim and edit BepInEx/config/jarki.fitness.cfg.

Treadmill multipliers do not change ordinary running. Severity penalties are fixed. Configurations are not synchronized; use matching settings across clients.

Updating from 0.1.x: existing config values are preserved. With the game closed, set SecondsPerLevel = 60 and RecoverySecondsPerLevel = 600 under [Muscle strain] and StrainBuildupMultiplier = 2 under [Treadmill] to adopt the revised balance. Previous 90/180 settings often healed fatigue entirely between ordinary sprints.

Requirements and installation

Requires denikson-BepInExPack_Valheim 5.4.2351 and ValheimModding-Jotunn 2.30.2. Single-player behavior was tested on Valheim l-1.0.21, native Linux.

Mod manager: install Jarki-Fitness and accept its dependencies. Use a separate profile and new disposable local character/world for your first session. Profiles isolate mods, not saves; back up valued saves.

Manual: close Valheim, install the dependencies, and copy the archive's plugins/Jarki-Fitness/ directory into BepInEx/plugins/. The DLL belongs at BepInEx/plugins/Jarki-Fitness/Fitness.dll. Remove any older manually installed Fitness.dll, including a copy under plugins/Fitness/; never keep two copies. Native Linux uses Linux Doorstop, not Proton DLL overrides.

Because the treadmill is a networked custom piece, the server and every client must have matching Fitness installations. This requirement does not establish multiplayer compatibility.

Uninstall

Back up your saves and remove all treadmill pieces before uninstalling. Loading a world without its custom-piece definition can lose those pieces. Close Valheim, then uninstall through the mod manager or remove BepInEx/plugins/Jarki-Fitness/. Uninstall/reinstall has not been runtime-tested.

Compatibility and troubleshooting

Multiplayer and dedicated servers are unverified. Windows, controller use, long sessions and unrelated-mod combinations are also unverified. Use a disposable local world before trying a shared or valued save. The packaged ZIP has not had a fresh mod-manager import test.

If the treadmill is missing, check both dependencies loaded, learn its ingredients, and use the Hammer near a workbench. Walking with low stamina is recovery, not a stopped workout. If you dismount unexpectedly, check nearby threats or blocking interfaces. For other issues, report game/mod/dependency versions, reproduction steps and redacted BepInEx/LogOutput.log errors. Never post passwords, tokens or private saves.

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