This Summer's Workout Threat-o-Meter
Ouch! Factor (Scale is 1 to 5, where 5 is maximum pain potential): 4 while leaning hard to one side to race an incoming storm; 2 while sitting on the beach the next day.
Paddle safely: Before hitting the water, stretch by your feet by rolling your ankles and pointing and flexing your toes. While paddling, keep your knees and ankles soft and flexible, Matthews says. Also try to root all four corners of your feet into the board, distributing your weight equally—even when you get tired and want to roll your ankles inward.
Ouch! Factor: 3, but the soreness might not set in until after you reach your destination.
Stride safely: Matthews suggests a vest, which is unlikely to affect your balance or gait, with weights that are 5 to 10 percent of your body weight (that would be 7.5 to 15 pounds for a 150-pound woman). Bonus: Walking with a vest not only burns more calories but also helps strengthen your bones.
Read more: Bob Green's favorite bone-building exercises
Ouch! Factor: 2 to 4, depending on where the sandbag lands.
Sweat safely: Matthews suggests starting with 4-pound sandbags, and giving yourself time to adjust to how they affect your grip and your balance before progressing to bigger, heavier weights.
Ouch! Factor: 4 if you don't switch your stroke or your style, and 5+ if your strain becomes a tear (pay attention to the pain and back off before that happens).
Swim safely: While swimming freestyle, make sure that all five fingers dive under the water together, with your palm facing down, Matthews says. If your thumb is going in first, you're over-rotating your shoulder. She adds that because we rotate our shoulders inward all day long while typing and driving, for instance, we all need to make sure we're stretching the opposing muscles—and this is especially important for swimmers. "Any move where the thumb points up and back can help," says Matthews—like this Pilates-inspired standing pose.
Ouch! Factor: 3 to 4. Rest is the best treatment for these types of lower-leg strains, which means you could be off the trails for the rest of the summer. (Bummer factor: 5+)
Climb safely: Taking smaller strides on rocky patches will help keep your hips over your feet, Pohja says.
Read more: Hiking mistakes to avoid
Ouch! Factor: 5 if you continue to heel-toe it on concrete or asphalt. (We're referring to physical pain, not the aesthetic pain some people feel while looking at minimalist shoes.)
Sprint safely: Whether you want to run barefoot on the beach or wear minimalist shoes on the sidewalk, start off walking or jogging slowly, and focus on landing on the middle of your foot, not your heel, Matthews says.
Read more: The pros and cons of barefoot-style shoes
Ouch! Factor: 2—this sensation is more uncomfortable than painful, but it will still distract you from your ride.
Cycle safely: Your elbows should be slightly bent, not locked, and your arms should be perpendicular to your torso. If you had your seat fitted at a bike shop (i.e., you've got the right setup) but the numbness is continuing, it's possible that your hands are being lulled to sleep by the vibrations from aluminum handlebars. Loosening your grip, wearing padded cycling gloves or investing in handlebar dampers or plugs that absorb some of the vibrations can help.
Next: Addictively fun exercises your trainer doesn't want you to know about