Biggest problem is the detector search coil weight causing the detector to be unbalanced.
Now needing you to use more wrist muscles tensed up to keep the detector balanced when swinging.
Which also, naturally causes you to grip tighter. Too big or small of a handle diameter, can also be an issue.
Then the handle angle can make things worse:
Then where you grip and arm cup height, if your forearm is not parallel to the shaft when swinging also causes wrist and arm fatigue.
Either the arm cuff needs to be raised or your hand needs to be lowered on the handle. Correct handle angle can fix some of this.
Adding rear counter balance weight on a straight shaft, makes it harder to to end and start the swing from left to right, if the detector was unbalanced to start with.
Coil and where the lower rod attaches will also make a difference. Coil mounted closer to the center has better balance.
The above can be an issue with any detector that looks like a cell phone on a stick. All the weight in in the handle/control box and search coil.
Everyone is built different with physical strengths and weaknesses.........................................................
Will add this note, any cell phone on a stick detector made to be waterproof and used for both land and water hunting, will need a heavier coil. So it will not float or fold upwards when submerged and
no needed extra wrist force to keep the coil down. Anyone ever have the Whites Surfmaster Pi and not get the diving coil?
Nokta/ Makro has been tweaking the handle angle and position on the shaft. The handle itself and angle seem to be correct. They did a great job on the Anfibio handle and Simplex handle.
But, still coil heavy and not balanced.As mentioned above the extra search coil weight was needed for water hunting.
Here's the killer detector for best handle ergonomics. The original Quest Pro. Second best was the Q40. Plus the balanced just about perfect with the lightweight 5x9 or 5" coil. If the detector is balanced properly, its natural position would put the coil parallel with the ground. Test your detector like the picture below. Hold it in your normal hand grip position. Release your grip and see where it balances.
You could swing all day, felt as light as a Tesoro. Quest used a lightweight filler epoxy to pot the coils, making them lightweight. With this is mind maybe those other brand machines
should offer a lightweight optional coil for land hunting?
I am all for ergonomics and detector balance, so I attempt to mod those I can to fit my needs. Right now making my own custom grip for the Simplex to be used on a round tube light weight straight shaft
and lower rod using the 5x9 coil. Will be interesting to see how it swings when completed.
Lots of arm cuffs are preset to being too wide, so it forces you to where the arm strap. If the arm cuff is too wide and made out of metal, bend it it for a somewhat snug fit. If plastic Heat with a heat gun, then bend it into the proper fit. Add a block under the control box to get your wrist and forearm into a better position.