The importance of upper body strength to a police officer is unquestionable. To effect the arrest of a non-compliant or combative suspect requires that you have enough strength to secure his arms for handcuffing.
If handcuffing suspects was the only task we ever had to perform, having tremendous upper body strength might be sufficient. But, when you consider the possibility of having to deliver an effective strike with a baton or personal body weapon, evade an attack, shoot while moving, or quickly move to a position of cover, the importance of stance, footwork, and lower body mechanics is evident.
Stance is so hotly debated, particularly as it relates to shooting, that an entire book could be devoted to this topic alone. There are "die-hard" proponents of both the "Weaver" and the "Isosceles" methodologies. While it is not my intent to compare and contrast these shooting techniques, I intend to provide a glimpse as to the advantages and disadvantages of each strictly from the perspective of stance, footwork, and lower body mechanics.
The Weaver method involves the shooter standing in a bladed position, with his shooting side to the rear. This position makes you less of a target, whether in a shooting or fighting situation, and helps to protect your centerline targets (eyes, throat, solar plexus, groin, etc.). Another benefit of this bladed position is that it keeps your gun further away from a subject than if you were facing the subject squarely. For these reasons, officers typically use this type of stance when contacting subjects (often referred to as the "position of interview").
As you can see, the Weaver stance has its strengths. However, critics of this stance are quick to point out that our body armor is designed to offer more protection from the front than from the side. This stance tends to expose the "Achilles heel" of our body armor, which is the area under the armpit, above the armor. Rounds impacting this unprotected area have resulted in the death of countless officers.
Many officers consider this stance to be awkward or unnatural. Proponents of the Isosceles stance (described below) claim that in a shooting or other highly stressful incident in close quarters, the officer's instinctive response will be to square his body to the threat, regardless of the officer's prior training. Another drawback to the Weaver stance is that it limits your field of fire, while hindering your ability to move quickly in any direction.
The Isosceles stance involves standing squarely to face the threat, with your feet approximately shoulder width apart. Many officers prefer to place their dominant side foot back slightly. This is arguably a more natural response to a spontaneous type of assault. From this squared position, you can easily move in any direction. You can also achieve 180-degree coverage without stepping, by rotating at the waist like the turret of a tank. This stance also places the bulk of your body armor between you and the threat.
The Isosceles is not suited for contacting subjects, because your centerline is exposed. Also, since your feet are positioned along the same line, you could very easily be pushed backward and lose your balance. Additionally, this stance does little to protect your holstered firearm.
Remember that the epitome of a good stance is one that provides both mobility and stability.
In the case of footwork, think "small steps" when shooting and "big steps" when fighting.
Small steps enable you to move smoothly while minimizing head and muzzle bounce. This translates to a more stable shooting platform and more accurate rounds on target.
When moving forward with a "heel to toe" step, with your knees bent and your body leaning forward slightly, in an aggressive posture, you should feel your weight distributed on the balls of your feet. This allows you to pivot quickly in any direction.