What are the rules on tackling and obstruction?

Under the FIH Rules of Indoor Hockey:

Tackling

• You must not tackle unless you're in a position to play the ball without body contact.
• Sliding tackles and other overly physical challenges that take an opponent to the ground, and could cause injury, should attract match and personal penalties.
• You must not touch, handle or interfere with other players, their sticks or their clothing.

Obstruction: you obstruct if you:

• back into an opponent;
• physically interfere with an opponent's stick or body;
• shield the ball from a legitimate tackle with your stick or any part of your body;
• run in front of or block an opponent to stop them playing the ball (third-party or shadow obstruction). This includes attackers blocking defenders or the goalkeeper at a penalty corner.

A stationary player receiving the ball may face any direction. A player with the ball may move off in any direction, except bodily into an opponent or into a position between the ball and an opponent who is within playing distance and trying to play it.

Also: no lifting your stick over other players' heads, and no playing the ball while lying on the floor or with a knee, arm or hand (other than the stick hand) on the floor.