Perception versus reality. An interesting study published in the Journal of Strength and Conditioning Research compares how subjects rated the difficult of their training with the number of calories the effort actually burned.

Nine active college aged men performed a circuit of 15 reps at 10 different weight training stations using 40% of their one rep max. Then they ran on a treadmill at a speed that would equal the heart rate they reached while circuit training.

Although they burned an average of 168 calories during the circuit training workout compared to 244 calories while treadmill running, subjects rated the circuit training effort a more difficult 6 on a scale of 1 to 10 compared to the much lower 4 rating they gave treadmill running.

Via OptimumNutrition.com

Contrast training works the same muscle groups with both  resistance and power movements. Think following a set on the bench press with medicine ball throws or doing squat jumps after barbell squats. A study published in the journal Medicine & Science in Sports & Exercise suggests this type of training is more beneficial to athletes with lower strength to power ratio.

Researchers had 22 rugby players perform 2 sets of squat jumps using 30% of one rep max (1RM) after 6 reps of half squats using 85% of 1RM. They found that peak power enhancement was not related to 1RM, but was negatively correlated to your power to strength ratio. Performance enhancements from contrast training are more likely when there’s a lower ratio between baseline peak power and 1RM half squat strength.