Junior golfers who learn and play golf swinging heavy clubs are at increased risk for injury. Common injuries in juniors who train excessively with heavy clubs occur in the lower back, wrist, and elbows. Swinging heavy clubs puts increased torsional stress on growth plates located in the joints.
Tendons are stronger than developing bones. Excess shear forces applied to young bones can result in distortion or fractures. Young golfers anxious to please their parents or their peers may not admit to the joint pains or muscle pains that indicate injury until real and sometimes irreversible damage occurs.
Over-training with heavy clubs in early adolescence when growth spurts occur is to be avoided. The lower lumbar spine is especially vulnerable. The L1 disk can be pulled forward resulting in posture defects and pressure on spinal nerves. We've also seen injuries to the thoracic spine. Clinical treatment is needed as soon as signs of injury are detected.
The brain is also developing and remodeling as growth continues through adolescence. Awareness of the body and body parts in space -- proprioception and 3D integration -- can be affected. It's normal. Trying to overcome a temporary issue with feel and coordination by placing a heavy club in the hands of a young golfer can lead to the wrong outcome.
What's a heavy club? Just about any club with a heavy steel shaft. The shaft is the main determinant of club weight. Graphite shaft weights can vary over a 100 gram range. Steel shaft weights can vary over a 70 gram range. Except for equipment intended for young juniors, club head weights -- grips also -- vary over a much narrower range.
Any standard adult club with a 120 - 135 g steel shaft and a standard grip is a heavy club. Does anyone need it to win top tournaments at the highest level in golf? No. The most presigous events have been won by golfers playing 90 - 100 g shafts, sometimes at relatively soft flexes. Extra stiff heavy steel that feels like rebar is not required to win.
Why do some junior golfers play heavy steel shafts? It can start with parents or relatives giving an old discarded adult set to their junior golfers. Cut them down to a more favorable length, add a grip that's too large, then it's off to the range or the first lesson. Other times it's a misinformed view that heavy steel and an extra stiff flex is needed to feel the club during the swing.
Bottom line, if your young golfer is practicing and playing golf with heavy clubs built with heavy stiff steel, find a professional club fitter who understands the needs of junior golf. It's entirely possible to play golf and win tournaments at the highest level with light weight clubs. And get a scholarship or two along the way.