Unless I am using a small knife like a SAR4 or similar where I hold the knife towards the rear of the grip to maximise leverage...I just hold the knife normally by the grip...so on a NMFBM or DFLE or FBMLE size knife the grip is a standard one.

The thing I try and do which makes chopping far more effective is I start chopping a "v" at the distance appart as the limb or log is deep. This gives, technique wise, a lot more ability to use less strokes and take big deep chips out of the wood. I also try and go for "aim" rather than power because following up a cut in the same "path" as the first is infinitely quicker than missing and starting another cut at the "outside" starting point.

Other points are "footwork" and "positioning"...I try to ensure any follow through or even a missed swing will pass safely by...and from experience the things to be careful of are using your foot/boots to anchor a log if leaning it up against something to get it "off the ground" for chopping. I was testing the SAR4 LE on chopping and a glancing cut had a resulting cut in the rubber sole of my boots! Lesser shoes on and I would have had a bad injury....

For this reason I am not a big fan of using a small end chopping knife...the lack of weight and power tends to have you compensating with an attempt at fast multiple strikes....which are "uncontrolled" after a while and hence accidents can happen. A large knife like a NMFBM is safer in my view because it works so well and you can use the "earth" more as a safety cushion "zone" to stop a follow through swing by using the length of the blade to maximum effect.

It is not just "body" position but also "log" position....Mr P has at Ban's place a table specially done for anchoring wood and chopping at that height has a maximum ability to bring in hips and upper body for strength.

Chopping in the Woods is a different matter but if felling a tree I cut a "V" into the stump to wedge other limbs into it for chopping logs....this helps if the stump is kept at waist height.