SKLZ Speedsac Adjustable Weight Sled Trainer for Sprinters, 10-30 pounds

I've got a skinny six year old who weighs under 50 and he's nothing but knees and elbows. I also have an 8 year old that's 81 lbs and built like a brick s&^thouse. The waist band around the speed sac accommodates both (although is more acclimated to fit my bigger boy).The outside of the speed sac is durable, like a tough rubber mat that you'd put in your pickup. The velcro for the belt does it's job perfectly. The loop joining the bag and belt is big and solid, and the hook mechanism to hold the three 10 lb sand sacks is more than adequate. Nothing is falling out of this.Strap the belt on you, walk up to the line, then go. For my boys, I use 20 lbs for my 8 year old and either 10 lbs or nothing for my youngest. The bag is heavy enough for a little sprout that you don't necessarily needs lbs of resistance.Like other SKLZ products, this one comes with a workout poster. One one side, a poster with recommended drills for only the speed sack (number of reps, distance, etc) in a 6 week format. On the other size, a 6 week workout program that combines the speed sac with other SKLZ products (such as the speed hurdles, quick ladder, viper 360, etc.), and both have beginners/advanced adjustments.It also comes with a DVD, but the DVD isn't just for the speed sac. The DVD gives demonstration videos for most of its products. Each video clip is around 20-30 seconds in length (speed sac has three videos, if I remember correctly). Each video demonstrates regular speed and slow motions with different angles so you can see and teach proper form.As for its effectiveness, that'll remain to be seen. But in football, your first step is the most important step. If you can get off the line quickly and keep improving that quickness, you'll improve your game. On the line, first man off the ball should win the battle. This product improves first-step speed and overall speed. It will help you improve your stride, your body lean, and your leg strength.The three bags, which you have to fill with sand ($4 for a 50 lb bag of sand at OSH), have a handle on one side of the bag so you can carry then down by your side while you're performing walking lunges. Great way to wrap up some 5 x 15 yd runs.

I've had experience with this brand before in a class so I knew I wanted this; I just didn't know if I wanted to go with this brand or a more expensive version. I read all reviews, especially negatives, and decided to try them. Because I've used them before, I knew not to use it on pavement or the webbed edging gets torn up. As to the bagging/sand leak issues... I'm still working with it because I ran out of sand and the Ziploc bags I had were square so it made it difficult to get the right amount of sand in each pouch, but that's really just a technical issue on my part that I've not gotten around to finishing. As to the leaking - frankly, if you're doing an outdoor bootcamp, who cares? I teach inside and out so I wanted to make sure they didn't leak. If I were strictly outside, I'd fill them as is, possibly duct tape the top as some have, and let'er'rip.Overall, they are absolutely FINE for the money and the Ziploc solution is best if you're primarily inside or in and out. Otherwise, filling the pouches w/out liners is going to be fine and you'll just have to refill them from time to time. I would DEFINITELY buy them again (and, in fact, intend to on my next equipment purchase) and would recommend them for anyone based on the above.Just remember to keep them on gym-type floors or on grass so the edging isn't shredded (which may not even affect them, I just prefer to keep them "pretty").

I just received the product and I'm a little disappointed. I LOVE SKLZ products and have purchased at least 10 of their training products in the past. I have ALWAYS been extremely satisfied. The quality of construction and materials used in their products has never been an issue and that is why I completely trust the SKLZ brand. This product seems to be no different as it looks well constructed and seems to be made of materials that are built to last. I was VERY eager to receive this product in order to use it with my 9-year old son to help him build his leg strength and speed for both baseball and basketball. What athlete isn't served well by being faster than his/her competition? I was even going to work WITH him (obviously with more weight) to get in a little better shape myself. When I got the package I was surprised by how light it was. It was fairly heavy but certainly NOT anywhere near 30 pounds. I opened the product and couldn't find the weights. I then found on the back of the box in an incredibly tiny font "Filler not included" as the intention of the weight bags is that you fill them with sand. I then inspected the bags and they look very well constructed and they even have a double Velcro seal system seemingly to hold the sand inside the bag. Since this is a SKLZ product I'm fairly certain this double Velcro seal system will work well. I wanted to start training immediately, but it will have to wait. I checked the product description and there is NOTHING regarding the need to get my own sand! It is advertised as if this product is ready to go right out of the box. I now have to go buy a bag of sand. Since I have had to fill the base of my basketball hoop with sand several years ago, I seem to remember that sand is typically sold in 50 pound bags. So not only do I have to go buy sand, but I'm going to have an extra 20 lbs of worthless sand on my hands. I guess this is OK, but I sure wish the product description was more complete. Maybe SKLZ modifies the product to include 5 bags so I can use all 50 lbs of sand? Or maybe they offer the option to purchase 2 more bags for additional flexibility. This would allow me to use 2 bags for "additional exercises" (as promoted on the product box) AT THE SAME TIME as using 30 lbs in the Speedsac? I guess no one at SKLZ thought about that. I'm sure I'll be happy with the product - but I sure wish they better described the need to fill these bags with sand. Maybe they think people will "pass" if they know the bags need to be filled with sand? Not sure why the product description doesn't make this clear. I'm giving it 4 stars ONLY because it didn't include the weights as expected. At this point I would recommend this product as it seems well constructed and with top quality materials. I'll update this post in a month or so to let you know how the speed training is progressing as well as how well the product has held up.