History of the piece aside, it represents to me the equity of intelligence and physical strength.
The lion strikes at the man's heart (his inner strength) and legs (his support) to bring man to his four-legged level. The attack, though theoretically effective, exposes the lion's weakness.
Holding the lion's ear to steady his target and avoid its teeth, man strikes at the lion's exposed underbelly, showing his cunning for seeing opportunity to affect dominance, despite his inability to thwart the majority of the attack.
Based on the effect of the individual attacks, it is likely neither will survive. Thus, superior intellect does not trump physical strength, yet neither does the inverse apply.