Your trainers may have stood idle in a closet over the winter, and now you’re ready to resume your running regimen or other sport activity. If so, be sure to increase the intensity gradually, doctors say. If you don’t, you increase the risk of straining – and at worst rupturing – an Achilles tendon, warns the German Society for Orthopaedics and Trauma Surgery (DGOU). The Achilles is the thickest and strongest tendon in your body, connecting your calf muscles to your heel bone. Ruptures occur most frequently during sport. Along with going easy at first, the DGOU advises strengthening your calf …