New research supports the benefits of hiring a qualified personal trainer to help you attain your fitness goals.

Twenty men ages 18 to 35 were placed on a 12-week resistance-training program.

Half the group trained unsupervised and maintained their own workout logs. The other half received one-on-one supervision with a certified personal trainer.

In addition to keeping track of their workouts and charting their progress, the trainers provided spotting and advice to participants and made sure training loads were increased progressively.

Unsupervised participants made changes to their programs using the same principles and were self-motivated.

Both groups achieved significant strength gains; however, the supervised group also made significant improvements in body mass, fat mass and fat-free mass.

Researchers suggest that the trainer encouraged participants to use and tolerate greater training loads, thus eliciting greater gains than those who self-selected their training loads.

Fifteen seconds is better than five, though five is still better than nothing when it comes to improving flexibility.

A new study out of the United Kingdom suggests a significant benefits from holding each stretch at least 15 seconds as opposed to five seconds or not stretching at all.

Twenty-four college students (average age 20) participated in the five-week training study.

Those in the five-second group performed each stretch nine times, while those in the 15-second group did each stretch three times.

While both groups improved their passive range of motion, those who held their stretches longer showed greater improvements in active range of motion as well.