Sports, Fitness, Recreation, and Leisure magazines
- Ice Hockey: Forces in the Check
- Ice Hockey: Slapshot Velocity and Hockey Stick Technology
- Iditarod
- Iliotibial (IT) Band Friction
- International Anti-Doping Agreement
- International Federations
- International Intergovernmental Consultative Group on Anti-Doping in Sport
- International Olympic Committee (IOC)
- Ironman Competitions
- Ito, Midori
- Jackson, Vincent Edward
- Jahn, Freidrich Ludwig
- Jenks, Herbert
- Joint Noise: Popping and Cracking
- Jones, Arthur
- Joyner-Kersee, Jacqueline
- Jump Rope Training
- Juvenile Obesity
- Karolyi, Bela
- Klein, Gary Gordon