Single Russian-Twist

1. Starting Position:
- Stand with your feet shoulder-width apart.
- Hold your arms above your head with your elbows slightly bent, palms facing each other.

2. Engage Your Core:
- Tighten your abdominal muscles to stabilize your torso. You should feel your core engaged.

3. Movement - Twist:
- Rotate your torso to the right, keeping your arms elevated.
- As you twist, lift your right knee up towards your chest, bringing it in alignment with your hip.

4. Return Position:
- Lower your right leg back down as you return your torso to the starting position.
- Quickly transition to the left side, twisting your torso to the left while lifting your left knee up towards your chest.

5. Repeat:
- Alternate sides in a fluid motion.
- Continue twisting from side to side for a set duration or number of repetitions.

Tips:
- Keep your movements controlled to avoid straining your back.
- Focus on using your core to power the twists rather than your arms.
- Maintain a steady pace and breathing throughout the exercise.