Whether you are 9 or 90, there are things someone your age should not be doing in the gym. Key to staying on the path to fitness rather than the ER are professionals who understand the basics of exercise and the specifics for the age groups they are training.

  • Infants and toddlers - Although they might seem like indestructible Gumbys, in reality they have a vulnerable spot on their heads, weak spines and are top heavy, which is why they are so prone to taking nose dives. Before you take your little bundle of joy to an exercise or play class, check out the credentials of the staff and review their safety guidelines.

  • Youth - Growth plate damage is one of the major concerns with children. If they are being coached, parents should be involved. A winning record can be built on broken bodies. Vet the coach and go to practices to see what goes on. Listen to your kid. Extreme fatigue can be a warning sign.

  • Teens - Their bullet-proof attitudes can lead to over-training, lifting weights that are too heavy and use of performance enhancing drugs. A good mentor in the gym is a big plus but be sure there are real credentials, not just muscles.

  • Adults - Don't be a weekend warrior. Have an exercise plan that is built on realistic goals and your current physical condition. Consistent and regular exercise is the key. Hire a good trainer with a degree in exercise physiology. Being an ex-Marine is not a qualification. Hardcore workouts that hurt are stupid.

  • Seniors - Even for those who have kept in good condition, aging bodies present challenges such as arthritis, diabetes, loss of muscle mass and weakening joints. There's a new term for the injuries 60-somethings get running around like they are 40 --- Boomeritis. Your trainer should have advanced knowledge in senior fitness. While that young, hard bodied athlete may look the part, chances are he knows squat about trainer a 50-something.