Look no further — you can build strength and muscle in your core without sit-ups, and here's the move to try
Focus on learning to engage your core at all times, slightly tucking your pelvis toward your spine to avoid arching your lower back. Drive through your hands and shoulders as you draw your feet inward ...
This Cardio Hack Boosts Calorie Burn by 15 Percent Without Feeling Harder
Practical tip: Periodically swim with your head up, looking forward, for up to 20 strokes. Called the "lifeguard swim," this ...