SAND BALLS and SAND BAGSIn a variety of weight-resistance training applications, plain old sand (just like the stuff you find at the beach) is invaluable. The sand inside of a sand ball, sand bag, Fitbag, or weighted vest is constantly shifting around, which means that the center of mass moves with the user, and the user therefore has to work harder to adjust to—and try to stabilize—the shifting weight. This means a more challenging workout than workouts using solid weights; the element of instability forces you to work on your balance, and your core gets a good workout. Plus, with certain sand-filled weight-training tools, weight changes are easy—you just add or subtract sand to achieve the desired weight load. Sand-filled training tools fall into the category of weighted resistance training. Workouts using weighted resistance help increase power, improve strength, and enhance endurance, grip, and mobility. Q: How much weight should I start with when training using sand-filled products? A: The weight of the sand-filled training product you choose depends on your level of fitness and what type of exercise you’re doing. For instance, SandBells® come in 12 different weights, with 2 pounds being the lightest and 50 pounds being the heaviest. SandBells® can be used for lifting, tossing, and throwing exercises, so beginners will want to start with the lightest weight and work their way up. Performance Bags, on the other hand, can hold up to 100 pounds of constantly shifting sand, which means these are more suited to advanced users performing chops, tosses, carries, and drags. Boxers and martial-arts athletes often use Performance Bags for training, since the bags are almost as big as the human body and the shifting sand inside simulates the way a body is constantly moving. Q: How are FitBags supposed to be used? Someone at my gym had one around their neck, but someone else was simply lifting theirs off the floor. A: They’re both right; FitBags can go around the neck or shoulders, or can be held in the hands similar to a barbell or dumbbell. FitBags have durable elastic handles and tapered ends, so they’re easy to grip and reposition. Q: Do SPRI’s FitBags come filled with sand? A: Yes, FitBags are pre-filled with sand. In fact, the tough construction of FitBags prevents breakage and leakage, which means the sand won’t come out but also means the user is unable to add or remove sand to change the weight of the bag. Q: Do SPRI’s SandBells® come filled with sand? A: Yes, just like FitBags, SandBells are pre-filled with sand, and the sand stays secure inside, meaning that the user is unable to add or remove sand to change the weight. Q: Do SPRI’s Performance Bags come filled with sand? A: No, Performance Bags, available in 50-pound and 100-pound capacity, do not come pre-filled with sand. You can find bags of filler sand at your local hardware, home-improvement, or discount store. What’s great about Performance Bags, though, is that they come with six separate filler bags that fit inside the larger bag. You simply fill each inner filler bag with sand, and then you can add or remove the smaller filler bags as needed to achieve the desired total weight for each workout or each user. Q: How does the Weighted Vest work? A: The Weighted Vest works by adding an additional weight challenge to other exercises. For instance, you can wear it while walking, running, jumping rope, doing pushups, etc. The vest comes with 10 flexible, pre-filled steel-sand bags that weigh 2 pounds each. You simply add or remove the bags from the vest’s pockets to achieve the desired weight. Large overlapping hook-and-loop straps keep the vest securely in place on your body as you train.