Effect of lower body aerobic exercise before resistance training

• In 2014 the Journal of Strength and Conditioning published a crossover study in which 14 men completed 30 minutes on an elliptical machine and subsequently completed back squats or bench press. Results showed that, compared to control settings in which the men completed no aerobic exercise, lower-body aerobic exercise significantly reduced the number of repetitions competed in back squat but not bench press. [Source]

Improved arterial stiffness

• In 2015 the International Journal of Sports Medicine published a study of 20 healthy young men which found that, compared to upper body resistance training, arterial stiffness was lower after whole body training and particularly after lower body training. The authors note that lower body or whole body resistance training may be preferable in individuals with arterial stiffness. [Source]

Squats Vs Leg press – Increases testosterone and growth hormones

• In 2014 the Journal of Strength and Conditioning published a crossover study in which 10 resistance trained men completed 6 sets of 10 repetitions of both squats and legs presses separated by one week.  Blood tests collected before and after exercises showed that squats increased both testosterone and growth hormone more than leg presses. However, squats also led to greater increases in cortisol levels. [Source]