Muscle strains are common. They can occur when you stretch or reach out past your normal range while running, playing sport or gardening etc. A muscle tear is more serious as some of the muscle fibres will be broken.
The best way to prevent muscle strains and tears is to include a warm-up programme before starting any exercise, and then cool down and stretch when you have finished the activity. Advice on warm-up programmes and cool-down activities can be obtained from your local physiotherapist or from the ACC website. You can also see some handy injury prevention tips here.
The sooner you get help, the faster you injury is likely to heal.
Following an injury, your physiotherapist can help restore you to full movement and also teach you how to prevent injuries reoccurring. Treatment will include an exercise programme, possibly with the use of some gym equipment to increase your strength and co-ordination and restore any movement lost in the joint.