Warlock

What are the factors for increasing hand speed earlier? I've read the following: 1. Work done on the club is via the hands on the grip and is defined by 'Force x distance moved in the direction of the force' . So theoretically the more work done on the club will add more kinetic energy to it . Therefore if you want to increase your hand speed , you might want to increase the hand path or increase the hand force applied along that hand path or both. Also if you want to do more angular work on the club , you could add more Torque via your hands or more angular distance or both. 2. Faster backswing can ensure that you have a larger starting force for the downswing. 3. Stretch shorten cycle at the top of the backswing (ie. in the 'external/internal obliques' + shoulder girdle muscles ) could provide the ability to add more force into the arms/hands in the downswing? 4. Having an increase in the lag angle in the downswing allows a greater force to be applied to the hands ( for a given torque in the upper body pivot). The MOI of the 'upper body + the arms/club' unit is less when the COM of the club is closer to the upper body pivot axis of rotation. Actually , if you bent your left and right arms more while also decreasing the lag angle , you'd theoretically be able to minimise the MOI and increase the forces in your hands (for a given upper body pivot torque). Might be good for increasing hand speed but might affect other aspects of your swing biomechanics to strike the ball where you want it to go. 5. An assertive upper trail-arm adduction while trying to passively straighten the trail arm can have at least 2 affects on the hand force if it's directed downwards and outwards across the grip. It can increase a component of the force more along the hand path and also create a clubshaft lagging 'Moment of Force' (which will help prevent an early cast and an increased MOI). 6. In some golf models it was shown that if you apply active hand torque 70 milliseconds before impact it would increase clubhead speed . If you did this before or after the 70 msec mark it would decrease your clubhead speed by impact. 7. Hand torque can help increase clubhead speed when the clubhead is moving slower but it is more efficient to apply an eccentric force across the grip to increase clubhead speed (when its moving faster). That means applying forces across the grip so that the in plane 'Net Force' component vector will create an MOF to increase the angular velocity of the club in the late downswing. 8. There is also kick velocity of the clubshaft that could add a bit of clubhead speed (if you let it). So I think the AMG video doesn't go far enough to explain the physics why having an earlier max hand speed can influence clubhead speed by impact.

Here is a video by Kevin Ryan demonstrating something called the 'Ryke Effect' (a mix of his christian and surname). He freely admits that he was wrong to infer that the 'effect' increases clubhead speed but he still claims it's a mechanism for closing the clubface . I thought that Dr Sasho Mackenzie's 'passive torque' concept (image below) could be a method to close the clubface without excessive muscular forearm rotation but this 'Ryke Effect' has thrown another possible mechanism into the mix . What are other members thoughts regarding the 'Ryke Effect' and is it a viable mechanism that could be used to square the clubface in the late downswing? I am assuming that to evoke the effect requires the upper lead arm to move on a steeper plane relative to the horizontal.

Wondering what the golfer has to do that will recreate those Pro movements (at the correct time in the whole kinematic sequence)?

Example for CCV or ROC (i'm assuming they are the same unless I'm mistaken). If Dr Sasho Mackenzie is removing the SPV (angular swing plane velocity) aspect of ROC , then he must be concentrating on the HTV and inclined swing plane angle, but that still has dimensions of degrees/time (or radians/time).

Note sure I understand the different ways that ROC can be measured. It's defined as 'how fast the face is closing' so I can assume it must be degrees/sec or radians/sec. And I suspect it is really only important during 'clubface/ball' impact period although one can assume it doesn't change much for measurements taken a few inches before impact. Yet Dr Sasho Mackenzie says the following : "All else equal, swinging the club faster will result in a higher RoC — what I call the swing speed knob — but you don’t start swinging slower as a result! The amount of lost distance will have a stronger negative effect on your score than any potential gain in accuracy. In my own research, I remove the effect of speed and describe RoC in °/foot. This enables me to compare across golfers or within a golfer who has returned with a difference in clubhead speed." So has he redefined ROC to be measured 'degrees clubface closure/distance clubface travelled' ? But it hasn't got the same dimensions as the original definition and I find that confusing.

Not sure how you would be able to block a variable in a golf swing but I suspect there was also a limit on his budget to conduct a more detailed investigation. For example , I think grip strength might affect ROC but not 100% sure. Or maybe the golfer has strong forearms and prefers to use muscular effort to square the clubface rather than some passive torque concept . In Dr Sasho MacKenzies research model he found that switching on a forearm torque generator (if timed correctly) could significantly increase clubhead speed , which in turn could increase ROC. Also, wouldn't one need a high frequency measuring system to accurately measure ROC just before and after impact (is 240 Hz enough)?

Maybe no relationship at all ! What criteria is used for 'Driving Accuracy'? For example , if the golfer misses the fairway by a couple of inches or snap hooks out of bounds are they both deemed a miss? Dr Phil Cheetham also found other relationships between golfer swing biomechanics and 'Handle Twist Velocity' (which is directly related to ROC in some formula). The article is here if your interested. Dissertation (philcheetham.com)

Many thanks.

Hi All Looking at this AMG video below , was wondering whether it is just a setup issue at address that can prevent the pelvis moving prematurely towards the ball-target line ? So if if there is unweighting of the trail leg in the early downswing (while the 'Core' rotates the pelvis and spins the trail hip) , the improved AMG setup with centre line of hips directly over the ankle joints (or slightly forwards towards the mid-sole) will cure this issue? But is there an explanation why this is a cure?

From what I've read regarding Dr Sasho MacKenzies, passive club squaring torque concept , there is not much active lead forearm supination (and/or right forearm pronation) torques being applied via the hands to square the clubface close to impact . So if that concept is being applied, isn't the ROC partially dependent on the degree of 'passive torque' and the amount of angular momentum it generates (around the longitudinal axis of the lead arm) as the left wrist ulnar deviates? The MOI of the 'forearm/club' unit reduces as lead wrist ulnar deviation occurs , and any residual angular momentum (caused by that passive torque) will increase the forearm rotation and overall HTV (Handle Twist Velocity) which in turn will increase the ROC. But I have also read Dr Phil Cheetham dissertation where he shows some graphs with a weak relationship between HTV (which has a direct relationship with ROC) and 'Driving Accuracy'. I'm not sure I've seen any research that compares driving accuracy with increased grip strength (where I assume there is less need rotate the clubface square during the downswing). Although less degrees of club squaring doesn't necessarily mean that the ROC would be smaller at impact.

I've been reading through this old but interesting thread and wondering whether I could ask a question about the above video and the 'regain' in the right leg flex by P5 in the downswing. I'm assuming the 'core' (not sure what that means exactly) is turning the pelvis , but what is stopping the right hip joint from spinning prematurely towards the ball-target line? For example , if the right leg is becoming unweighted in the early downswing and regaining some flex with the right heel raising up , wouldn't the 'core' be spinning the right hip towards ball-target line?

There is a good article by Dave Tutelman about grip pressure if you want to delve a bit more into the physics. Required grip pressure (tutelman.com)

I didn't post on the original thread as I didn't think it had any relevance to my real question which is about the possibility of dual supination of the forearms after P5.5 (ie. approximately when the lead wrist starts to ulnar deviate). When I looked at the above graphs on the Sandtrap thread and also that Kelvin Miyahiri you-tube video , it gave me the impression that the lead forearm was supinating while the trail forearm was pronating just after P5.5 . But after seeing the same type of graphs on the John Sinclair video (which I assume were retrieved from his TPI 3D AMM database of pga pro golfers) , he implied that the +y axis in the 'Trail Wrist Angle' graphs were measuring supination (not pronation) and that both forearms are supinating after P5.5. He also suggested that dual forearm supination was happening in the downswing in this video below. http://Chris Como and Jon Sinclair echoing my findings on supination - YouTube With the help of Dr Greg Rose I think I have enough information to now decide that the original TPI 3D AMM graphs had a report bug and that 'Trail Wrist' pronation actually meant supination. John Sinclair is claiming that dual forearm supination is actually happening in pga pro tour swings and here is a graph below showing graphs for the Trail forearm. I've no more questions but if you disagree with the above, I'd welcome your opinions.

Hi Erik I was asking whether there was an error in the TPI 3D AMM reporting of 'Trail Wrist Angles' that you previously posted (copy above). In fact , I've actually received another reply below from Dr Greg Rose (TPI) and he now confirms that there is/was an error. ""we helped AMM produce the avatar and gave them the data sets to use for normals on their software. It just looks like the report feature had the wrong unit (using a P instead of a S) in the report. But the graph looks good." So it seems that Jon Sinclair is correct , there is some dual supination of the forearms happening after release (although some of the TPI 'Trail Wrist Angle' reports are labelling the Supination 'S' as Pronation 'P'.

Erik I found the below TPI AMM graph from one of your old posts in 2016 and its says that the +y axis for the 'Trail Wrist Angles ' is showing Pronation. Further there is a Kelvin Miyahiri you-tube that implies the same (see link below). But then I was watching Jon Sinclair video with Larry Rinker (link below) and if you fast forward to 25:11 he shows 'Lead and Trail Wrist Angle' graphs where the +y axis are both supination. He says that both forearms are supinating just after release . I found this confusing , so I contacted the TPI Customer Services about this and got an email response from Dr Greg Rose who said: "Not sure why your software is saying pronation. That is definitely a mistake and should say Supination. The graph clearly shows supination and no golfer is 34 degrees pronated at impact Not sure what version of software you are using and I know that AMM is no longer around - but that is wrong!" So was the AMM Trail Wrist Graph that you posted (and its table below) showing pronation in the +y axis in error? --------------------------