One of your hamstring muscles is probably stronger than the other, an imbalance caused by the fact that most active adults have a dominant side – whether that’s the right or left. A study published in the journal Medicine & Science in Sports & Exerciseexamines whether this imbalance and hamstring weakness are risk factors for team sports injury.

Researchers tested the hamstring strength of 210 Australian football players before and after pre-season training. They found that low hamstring strength increased the risk of a strain up to four times, but that a strength imbalance of 10% between limbs didn’t have an effect on injury.

True Strength Moment: If this research is correct, it’s possible to train your way into a reduced risk of hamstring strains. Researchers suggest that stronger hamstring muscles can even reduce the risk of strains in older athletes as well as players with previous strain type injuries.


How To Optimize Protein Synthesis

Protein synthesis is an important process involved in muscle recovery and performance adaptations. It can be triggered by consuming protein, but how much is needed to maximize gains has been a matter of debate. A study published in the journalMedicine & Science in Sports & Exercise adds to the conversation with research involving experienced distance runners.

A dozen volunteers consumed formulas providing 70 grams of protein with 15 grams of added leucine or 23 grams of protein with 5 grams of added leucine after riding a stationary bike for 100 minutes of high-intensity cycling. Both supplements contained 180 grams of carbs and 30 grams of fat. Subjects received four servings during the first 90 minutes of a 240 minute recovery period. Fractional synthetic rate was optimized 33% with 23 grams of protein compared to the triple dose which only increased protein synthesis by 13%.

True Strength Moment: This classic case of less is more helped athletes achieve near maximal protein synthesis which contributed to optimal muscle adaptations during their recovery. For an interesting study on supplemental glutamine, read today’s Performance Blog



Muscle is built bigger and stronger during recovery, a process requiring rest and amino acids from protein. While many weight training adults know how a rapidly digesting post-workout protein shake can help kick-start the recovery process, not nearly as many have first-hand experience with slowly digesting protein shakes used right before bed. A study published in the journal Medicine & Science in Sports & Exercisetested bedtime casein shakes on 16 healthy young men.

An hour after a session of weight training that ended at 8 PM, subjects received a shake containing 20 grams of protein and 60 grams of carbohydrates. Before hitting the sack at 11:30 PM, some got 40 grams of casein protein while the rest received a placebo. Blood samples and muscle biopsies showed that casein elevated circulating amino acid levels and increased whole body rates of protein synthesis, improving net protein balance.

True Strength Moment: Protein synthesis was 22% higher for casein users versus placebo. Since recovery from weight training can take up to 48 hours to complete, keeping the aminos coming in your sleep seems like it might help support the goals of active adults working hard to increase muscle size and strength.