Sled work has a similar value to carries in building strength whilst not over-taxing the central nervous system, joints, tendons and ligaments. The reason for this being is that it is concentric only work. The concentric phase of a movement is the act of lifting/pushing the weight. For a squat it’s the part where you stand up. For most exercises you also have an eccentric (lowering phase). This will be the going down part of a squat. The eccentric phase is where the majority of muscle stress occurs during a workout. This is of course builds a great deal of strength and lean muscle however it does come a t price of taxing the body.
With sleds you are only ever moving the weight concentrically. This means you gain the benefits of building strength during this phase without the extra stresses caused by the lowering phase. This enables you to do a huge amount of training volume whilst allowing your body to recover from more traditional lifting.
The other benefit of sled work is that it’s shown to carry over into sprint speed and technique. Many studies have shown this happen due to the increased strength and power of the legs, a more stable midline and also the mechanics of sled work carry over well into sprinting.
So next time you see seld work programmed get down to the box and fire up your inner husky!