The Quarterback Throw Report breaks down a throw into key checkpoint and metrics to understand mechanics and performance. This article explains what appears on each page of the report and how to read it.
What You Receive After Processing
A processed throwing assessment produces three outputs:
PDF Summary Report — the multi-page report described here.
Overlay Video (.mp4) — your throwing video with full-body tracking, a colour-coded performance timeline, and summary data overlaid on the footage.
Data Summary File (.json) — for API users, containing input and processing data, subject information, video parameters, and the analysis summary.
How to Read the Colour Bands
Most metrics in the report appear on a colour-coded scale:
Green — great performance
Yellow — moderate performance
Red — an area for improvement
Each metric displays its name, the athlete's value with units, and the minimum and maximum of the range at either end of the bar.
Figure 1. Example metric with colour-ranges indicating performance. The metric name is on the top, metric value prominently in the middle, and the min/max ranges are on either end of the bar. The black line and arrow indicate that athlete's performance on that metric.
Where the bands come from: they are generated from our database of players across levels. A band is a population reference, not a true pass or fail.
Page 1: Throwing Mechanics Overview
The first page gives a high-level mechanics and performance summary built around four checkpoints in the throwing motion. A screenshot from your video is displayed at each one. These checkpoints are chosen deliberately: rather than fixed positions in the motion, they mark the moments where one segment hands power to the next.
Checkpoint | Definition |
Foot Strike | The point where the front foot plants into the ground. |
Back Hip Terminates Rotation | The point between the start of the throw and ball release where the back hip stops rotating. |
Torso Terminates Rotation | The point between the start of the throw and ball release where the torso stops rotating. |
Maximum Elbow Extension | Maximum elbow extension between peak shoulder external rotation and the post-release follow-through. |
Advanced Metrics
Metric | Unit | What it Measures |
Arm speed | mph | Peak hand speed over the entire motion, typically just before ball release. |
Release time | ms | Time taken to complete the full throwing motion. |
Peak hip rotation | deg/s | Peak hip rotational velocity. |
Peak torso rotation | deg/s | Peak torso rotational velocity. |
Page 2: Sequencing and Key Metrics
Kinematic Sequencing
Kinematic sequencing is the order and relative timing of key events through the throw, and it indicates how well power transfers through the body. A strong throw starts with the front foot rotating and planting into the ground. Power transfers up through the hips as they close toward the target. As hip rotation slows, torso rotation follows, continuing the transfer from the ground up. Finally the shoulder and arm carry that power through to ball release. Four events are ranked:
Foot plant
Pelvis rotation stops
Torso rotation stops
Maximum elbow extension
The report presents this three ways:
A sequencing plot with time-varying data for hip, torso, and elbow.
Sequence indicators ranking each segment by the order in which it occurred.
A Sequencing score out of 100, where higher values mean better transfer of power through the whole motion.
Key Metrics
Metric | Unit | What it Means |
Sequencing | /100 | Kinematic sequencing score. |
Overall throw score | /100 | Aggregate score for the throwing motion. Higher values indicate better mechanics. |
Acceleration score | /100 | A surrogate for how much force the thrower generates. Analyses the motion up to ball release. |
Deceleration score | /100 | How well the thrower handles the acceleration phase. Analyses the motion following ball release. |
Velocity efficiency | /100 | The average of the acceleration and deceleration scores. |
External rotation | deg | Maximum shoulder external rotation. |
Peak hip-shoulder separation | deg/s | Peak difference between pelvis and torso rotational velocities. Greater values mean the gap closes faster, with more potential to transfer power through the torso. |
Stride length | % height | Distance between the feet at foot plant, as a percentage of athlete height. |
Why acceleration and deceleration are separated:
Generating force and absorbing it are different skills. A thrower can score well on acceleration and poorly on deceleration, which is worth knowing. In the follow-through, much of the load on the arm is handled, and it is worth understanding how the athlete handles that skill independently.
Page 3: Joint Angles
The third page shows how joint angles change continuously across the throw. Body segments and rotation sequences follow International Society of Biomechanics (ISB) standards for a full-body model. Time-varying plots are grouped into two sets:
Throwing Arm — elbow extension, shoulder horizontal abduction, shoulder abduction, shoulder external rotation.
Trunk and Legs — trunk flexion, trunk rotation, lead knee flexion, pelvis rotation, hip-shoulder separation.
Page 4: Joint Velocities
The fourth page shows the angular velocity of those same joint angles, grouped the same way into Throwing Arm and Trunk and Legs. Where the angle plots show position, these show how fast each joint is moving, which is what underlies the sequencing analysis on page 2.
Pages 5 and 6: Tabular Data
The final two pages present the underlying numbers: specific joint angles at time points throughout the throwing motion, in table form. Use these when you need exact values rather than the time-varying data, like record-keeping, comparing throws side by side, or feeding into additional analyses.
Need Help?
If you have any further questions, our support team is happy to assist.
Contact Support: support@3motionai.com