Interactive Forum February 2025: Alex Michelsen Serve

[stotty]

Among the best in this category Delpo ?

There are always technical exceptions, even among top-level players...those odd one or two who defy conventional biomechanics and still perform exceptionally well using their own (or even technically “wrong”) method. The thing with ISR, however, is that it’s not just a case of one or two players defying the norms — there are quite a lot.

[BrianGordon]

Hi stotty - hope you are well. Two points:

1 - The ISR assessments out there are based on 3D analysis. It is problematic to make this assessment viewing video - especially in fast rotations where the elbow angle is >120 degrees. This is because ISR causes rotation of the humerus about its long axis. Video shows the motion of the surrounding tissue and it is established in the research that the humerus can rotate, or not, up to 70 degrees relative to the visible tissue. Even with 3D there are serious complications which was the subject of my doctoral dissertation.

2 - It is possible to bypass most of the ISR contribution and still hit a pretty big serve. The bypass is to extend the range AND duration of elbow extension in the upward swing and put a larger emphasis on wrist flexion. This approach is not uncommon at all, particularly with female athletes. Across the range of serve types (flat, slice, kick) the latter approach is limiting to what is possible with the ISR sequencing option so I would stick with that in your coaching - I do.

[stotty]

Hi stotty - hope you are well. Two points:

1 - The ISR assessments out there are based on 3D analysis. It is problematic to make this assessment viewing video - especially in fast rotations where the elbow angle is >120 degrees. This is because ISR causes rotation of the humerus about its long axis. Video shows the motion of the surrounding tissue and it is established in the research that the humerus can rotate, or not, up to 70 degrees relative to the visible tissue. Even with 3D there are serious complications which was the subject of my doctoral dissertation.

2 - It is possible to bypass most of the ISR contribution and still hit a pretty big serve. The bypass is to extend the range AND duration of elbow extension in the upward swing and put a larger emphasis on wrist flexion. This approach is not uncommon at all, particularly with female athletes. Across the range of serve types (flat, slice, kick) the latter approach is limiting to what is possible with the ISR sequencing option so I would stick with that in your coaching - I do.

Thanks for this.

One thing I hadn’t considered with ISR is that internal or invasive movement might not be clearly observable externally. It’s always struck me as the type of motion that would fully manifest outwardly.

And, yes, I always coach ISR. It’s relatively easy to encourage and apply in young players. I’ve just always been curious in its absence in some top players.