Free Forehand (Revolution Tennis)

Source file: Free-Forehand.pdf.txt

Domain: biomechanics / forehand-mechanics

Tier: reports/tier-1-high-value-gaps

Used in artifact: artifacts/reports/tier-1-high-value-gaps.md

Abstract

Forehand technique analysis focused on where on the head to strike the ball for maximum power.

Key points

Striking the ball at the racket's sweet spot maximises power transfer.
Off-centre hits lose energy to vibration.
Contact point relative to the body affects topspin / drive trade-off.
Frame stiffness and string pattern influence the 'feel' of contact.
Players intuitively learn to find the sweet spot through repetition.

Raw dump (first ~1000 words)

Free Forehand Dr. Jose Li (www.adhd-tennis.org) Page 1 / 24 Lesson 1: Manage mind and arm first The average ball flight time for an 80-mph forehand is about 1.3 seconds. At the end of the flight time, when the ball bounces forward, the receiver needs to respond to the ball by: reacting (human beings' reaction time is about 0.2 seconds) acting in multitasks (e.g., grip change, hit zone setup, and ball strike). The mind's path in ball striking follows the "3C" sequence. In about a 1second time span, as a process: Consider (requiring sound judgment), Converge (requiring good habits) and Concentrate (requiring discipline). Below figure illustrates my converging mind pyramid, which explains the mind target in a dynamic fashion. In the last 1/200th of one second (~5ms) at contact, when the ball is fully compressed, our eyes cannot see the ball on the sweet spot, but our minds can "see" the ball impacting the racquet by imagination and sensation. If our eyes are busy to radar everything (called "bouncy eyes") on court, our mind cannot guide to time the ball right. Page 2 / 24 Tennis play is done by arm and hand with the racket. However, arm and hand are "trouble makers" in most cases. Let us fix these "trouble makers" first. "Great Wall stance" is about the arm/racket position to receive ball at contact in forehand. This stance with two 90 degree bents between arm and racket focuses on the shape of hitting arm to support the racket contacting to the ball. It serves two purposes: 1) Keep the racket face vertical; and 2) support the ball hitting to the sweet spot of the racket. The "Great Wall" is a kind of buzzword reflecting the key meaning of this stance: the body support has to be as stable as the Great Wall! To achieve those two 90 degree bents with desirable orientation of your racket relating to the forearm, the two common instructions are: (1) Relaxing muscles in upper arm and shoulder, too much tension with tight muscles cannot achieve 1st bent (in arm). (2) Keeping the wrist "laid back" and locked at contact for forming the 2nd bent (in hand/racket). You can see the "GWS" is nothing new but highlighting the importance of the body stability behind the ball at contact. Let us create a visualization image in our minds with this "GWS" shown below: Page 3 / 24 Tennis is NOT about swing racket to the ball simply because of one reason: tennis is NOT baseball! In high-level tennis, skill of "waiting" the ball is even more effective than "chasing" the ball. In Chinese martial art, "standing still and straight" is taught first before any movements are taught. Swim coaching also starts with body balance instruction first (see shark fin stance photo below). Stance, Stance and Stance. That is why we should learn this static stance first in forehand. Page 4 / 24 Lesson 2: Contact, the core of tennis Great Wall stance (GWS) is for a solid contact between racket and ball. The contact is the "core" of tennis. Every thing is for THIS moment, which normally takes ~ 1/200 seconds. We address arm/hand position first, than to racket/ball interaction at contact. Understanding racket/ball interaction can make learning new forehand more "meaningful". Below photos show this kind of interaction right before and after the contact as well as in the forehand contact. Page 5 / 24 Those three factors controlling forehand quality, the pace (mph), spin (rpm) and ball striking angle are determined after contact. When we know how to make the right contact in play, we can make our shots more powerful and controllable. In forehand, there are 7 stroke keys in a hitting sequence: body turn, align racket cap to the ball, pull the racket, contact, lift and push the racket, wipe and follow through finish. I believe that the contact stroke key should be taught first. Other stroke keys are just designed for making better contact in a more repeatable fashion. Our tennis coaching should follow this logic path. What else can we learn from this contact stroke key? From high-speed video visualization analysis, we can study how tennis pro hits to contact. There are two important features in this contact phase: a) Racket and ball meet vertically at contact; and b) Ball is compressed at racket sweet spot. It happens in 5 ms, or 1/200 second, which cannot be clearly seen by human eye. Below photos show this critical moment (taken by 210 fps digital video): Ball is compressed! It can "stick" to the racket for a prolonged time. This is a simple concept for improving control. The question is how to get ball compressed? If we look at those forehand shots generated by tennis pros, we can find the following commonalities: a) Racket in vertical orientation Page 6 / 24 b) Hit ball on "sweet spot" "Vertical and sweet spot contact' is easy to say, but difficult to do. "Vertical" is the only 1 of 360 degrees the racket orientation needs to be positioned; and sweet spot is only small portion of racquet face. To meet both requirements at the same time, it is even harder! The most common coaching is: Look the ball at contact! Wait a minute; can Federer really see the ball at contact? Does it make sense to look the contact to see what really happens during the contact in 5 ms? The answer is yes as long as your mind (not your eyes!) is on the ball during the impacting. For most of players, it is easier to look at the ball than mind the ball at contact. Federer does see the ball at contact (with his mind). If other players feel the ball by their minds even though they do not look at the ball, they still can hit a clean shot. For a better contact, a pro normally trace the coming ball with his eyes up to the hitting zone. I believe that