If you've ever watched a soccer team's strength staff bolt rotational cable work and sled pushes onto a field session, you already understand the idea behind this guide: the best conditioning for one sport often lives in a completely different one. For tennis, that cross-sport gym is the water. Specifically, it's a kayak. The practical upshot: consistent paddling sessions build the exact stabilizer-plus-prime-mover shoulder package tennis demands, while the water's resistance