Sports require strength, power & explosiveness for general success. Increased size and muscle mass for some sports people (field based contact sports) from strength training is okay, however a weight gain to certain athletes would be troublesome. Most combat sports compete in weight categories therefore a weight gain of 2kg to a boxer will make the weight cut an issue.
Here are 6 tips to provide a boost in strength & power without a rise in weight & muscle mass:
Focus on singles, doubles & triples - This refers to reps range. To develop high levels of strength & power we must stimulate the nervous system. The nervous system represents your billions of power cables running through the body switching on muscles. Training these will boost strength & power without signalling muscle growth. When lifting heavy either perform 1, 2 or 3 reps...lucky you!
Stay away from the 5-10 rep range - Higher rep ranges in the 5-10 region will not heavily stress your nerves (power cables), rather they'll stress the muscles themselves. The muscles would like to respond to this stress by increasing size & density ensuring they're ready for the next bout, resulting in larger muscles.
High speed long rest activities - High speed activities such as box jumps, 10m sprints, Snatchs, KettleBell swings & MedBall Throws require extremely high movement speed. These exercises heavily fire up the power cables of the body delivering tons of electricity to muscles which can be expressed as power. Long rest periods must be employed ensuring a complete recovery before the next set...at least 3 minutes is ideal.
Never train to failure - When lifting to muscular failure a number of nasty compounds build up in our muscles, namely lactic acid and hydrogen ions eventually leading to a muscle building signal. You know this feeling as the intense burn within muscle when lifting heavy. A key concept for fighters is leave 2 in the bank. i.e. the set ends when you believe you only have 2 more reps remaining.
Add light mobility & core work into rest periods - As mentioned previously we require long long rest periods between sets of lifting, this gets boring making workouts long. Adding light mobility drills and core exercises into rest periods will fill up the time without having to perform these drills before or after the main session.
Pair low rep & high rep in the same session - Whilst mid range reps (5-10) aren't advised higher rep schemes (15+) are beneficial. Single & doubles should be performed early in the session whilst higher reps exercises such as glute, abdominal and upper back should be performed at the end.