Some last longer than others. Some are more effective than others, making them more than a "trend". The top three that are more than just "trends" are a new development in fitness worth checking out. 

 I got the power! Power production and the ability to be reactive is a quality that we lose as we age. The good news is that if you include certain exercises as part of your exercise program, you can develop power, elasticity and reactivity. In addition, you can work up to explosive exercises.. Start to incorporate power development into your fitness routine such as  box jump squats, concentric box jumps,and dumbell jump squats.

Women are taking over the strength-training floor. For so long, women stuck to the cardio machines and aerobics classes when it came to their fitness programs -- but the latest, hottest trend is women taking over the strength-training floor.. Women are realizing the benefits of lifting weightsmay outweigh other types of exercise that they can do. No longer afraid of bulking up, women are going after the fit, toned look they always wanted while gaining the benefits of strength, decreasing their risk of osteoporosis, boosting their metabolism, and reducing their risk of injuries.

Trainers aren't just for celebrities anymore. Personal training started as an elite service that only celebrities had access to. Fitness trainers coaching individuals in private sessions, semi-private sessions and group sessions is more effective for results and research has shown that having social support is one of the keys to long-term success on a weight loss or fitness program. Having someone to hold you accountable for your exercise routine is a key factor to your success..