Jogging becomes running when the activity is performed at a sufficiently high level that the intensity can only be performed for between a few seconds or several minutes for the average person. Running is one of the highest energy-consuming forms of activity/locomotion. Walking (both feet are on the ground at foot strike), and jogging (speed is such that only one foot is always on the ground), should both be performed consistently for longer periods before beginning any running program.
An individual must cycle at least twice as long as running to obtain a similar cardiovascular effect. Competitive athletes are able to sustain high running speeds for significantly longer periods than the average fitness enthusiast. Running requires speed of movement where both feet are off the ground in between foot strikes. This requires a very high level of exertion and requires that the ability of the individual be high enough to not only accelerate under control but stabilize and decelerate appropriately and safely (and under control as well). Natural muscular shock absorption reduces with fatigue and the impact is increased dramatically. Much like jogging or any other activity, if the individual cannot land softly to reduce the forces created from their own momentum and be able to maintain satisfactory form then the intensity level or speed should be significantly reduced until coordination and control can be established.
It should not be expected that everyone will run the same and there is no such thing as one perfect technique for everyone. Running on harder surfaces (concrete, asphalt, hard-packed sand, etc.) will require greater ability to handle deceleration forces (the ability to foot strike with controlled, soft landings), and running on softer surfaces (soft sand, mud, shallow water, etc.) will require greater ability to control concentric forces (the ability to push off and exert force with control and coordination). It is neither better nor worse to run on hard or soft surfaces, it depends very much on the ability and readiness of the runner (variable surfaces would be best).
It is important for the individual to:
1) Lean slightly forward to allow gravity to help pull the body forward during gait
2) Look forward about 10 yards to help maintain appropriate running posture and vision forward
3) Stride naturally to avoid overstriding and putting excessive stress on the body (uphill running at a 10% or greater grade can help increase stride length naturally)
4) Perform a natural arm action with wrists and elbows gently brushing the side/shirt with elbows flexed at approximately 90-110 degrees (depending on speed of movement and stride length) and the hands closed around an “egg” to emphasize a slightly closed but relaxed grip (all out sprinting may advocate an open palm with wrist/forearm in neutral position)
5) Perform slight downhill running (10-15% or lesser grade) to naturally increase stride rate or frequency of strides
6) Work on overall body strength with a well-designed resistance training program (lower body, core and upper body) to help the individual increase strength and coordination to find their own running form more efficiently (teaching efficient running form in a an individual lacking sufficient overall strength will merely complicate problems for the individual over time)