We've come a long way since Jack LaLanne opened health clubs and Olivia Newton-John begged for us to "get physical." While fitness trends have come and gone over the years -- take the ab belt, the NordicTrack and Power Plate, to name a few -- there's one trend on the rise today that isn't going anywhere any time soon: connected fitness. It's now a $14 billion a year industry, and it continues to grow -- health and fitness app usage is up 62% this year, and Flurry Insights data shows that health and fitness tracking apps are growing 87% faster than any other app category. Take a look through the timeline below and see how fitness has become more innovative and more infused with actual science in recent years. From apps to wearables to smart apparel, the connected fitness space is heating up, and we're looking forward to what CES 2015 will bring to those looking to get or stay fit.