| Abbreviation | Definition |
|---|---|
| LEAF | Leaders Encouraging Activity And Fitness |
| LFFL | low functional fitness level |
| LFOD | Life Fitness On Demand |
| LFPT | Life Fitness Physical Therapy |
| LIFW | Long Island Fitness and Wellness |
| LIRF | Leader In Running Fitness |
| LIRF | Leadership In Running Fitness |
| LOFT | Large Obstacle Fitness Training |
| LUFC | Lacey Ultimate Fitness Center |
| MAFC | Monroe Aquatics and Fitness Center |
| MAFC | Morrisville Aquatics and Fitness Center |
| MAGMA | Milwaukee Area Game Maniac Agency |
| MCDF | Mill City Dance Fitness (Fall River, MA) |
| MEEF | Motivating Everyone to Enjoy Fitness |
| MFC | Manitoba Fitness Council |
| MFF | Mark Fisher Fitness |
| MFIP | Monitored Fitness Improvement Program |
| MFN | Medical Fitness Network |
| MFS | Master Fitness Specialist |
| MFTC | Master Fitness Trainer Course |