If you want to keep your money local, give a gift certificate for a private yoga, Pilates, Nia, Zumba® or Personal Training session. I think it's helpful to choose an instructor or trainer who is willing to contact your gift receiver and encourage them to USE the gift certificate.
For the yogis on your list, sand bags are great for a home practice; save on shipping costs by purchasing them without sand. Use a bathroom scale and add play sand to fill the zippered canvas pouches. Yoga-paws are helpful when your favorite yogi is traveling without a sticky mat. A magic circle is a great addition to a Pilates practice; however, you don't have enjoy Pilates to use this highly portable strength equipment.
For the winter outdoor runner on your list, try my husband's favorite inexpensive pair of gloves found at Harbor Freight. The are called mechanic's gloves but don't let the name fool you. You can use them for cycling, kayaking and just about anything else you can think of. He keeps a spare pair in his car for whatever comes up. If your runner gets extremely cold hands, you can get the style that are insulated; also inexpensive.
For general exercisers, replace their old style stability ball with one that has sand; they are usually referred to as “stay-put.” These are much easier to manage because they don't roll all over the room, plus the ball increases the difficulty of some exercises. Balance pods are great for increasing core activation, and reactionary balls are helpful for training quick reaction to movement. Small squishy weighted balls have many fun uses to spice up exercise routines.
Gift cards for music downloads are a great gift item since many people don't exercise unless they have music to keep them motivated. For the kids and low budget gift givers, design some coupons. Coupons for serving as a walking partner or personal motivator will will help your loved one increase their daily activity.
Give the gift that encourages healthy living!