Rotation Lab Report Roll Physics Lab
Biomechanical Analysis: Lesson 01
Name:
Date:
Mission Objective
To investigate how body shape (radius of rotation) affects rotational velocity and stability during forward and backward rolls.
I. The Physics of the "Tuck"
Consider the Law of Conservation of Angular Momentum . If you want to spin faster, should your mass be closer to or further from your axis of rotation?
Hypothesis:
II. Field Testing: The Forward Roll
Perform 3 forward rolls with different body shapes. Rate your "Rotation Speed" and "Stability" (1-5).
Variation Tucked (Chin to chest, knees in) Loose (Legs away, open back) Piked (Straight legs) Rotation Speed (1-5) Stability Rating (1-5)
III. The Backward Roll Mechanics
The backward roll requires more explosive force to overcome gravity. Identify the two most critical biomechanical "Fail Points" observed during your practice today.
Fail Point 1:
The Correction:
Fail Point 2:
The Correction:
IV. Conclusion: Momentum Mastery
Explain why "tucking" the body closer to the axis of rotation increases the speed of the roll. Use the term "Moment of Inertia" in your answer.
Biomechanical Spec: 9.PE.G.01
UNIT: TUMBLING DYNAMICS
Roll Physics Slides Roll Physics
The Mechanics of Rotation
Biomechanical Series
Lesson 01
The Ice Skater Paradox
Why do figure skaters spin faster when they pull their arms in?
"Angular momentum is conserved. When the radius decreases, the velocity must increase."
Body Mass Distribution
Key Concept: Center of Gravity (CoG)
Definition
The point where the weight of your body is evenly dispersed and all sides are in balance.
In a tuck, your CoG moves closer to the axis of rotation!
AXIS OF ROTATION
Anatomy of a Roll
FORWARD PHASE
01. INITIATION
Shift CoG forward past the base of support (toes).
02. COMPRESSION
Decrease Moment of Inertia by tucking tightly.
03. TERMINATION
Increase radius to slow down and find feet.
Safety: Keep chin to chest to protect cervical spine!
Time for Field Testing
Grab your Roll Physics Lab Report.
We are testing 3 variations: Tucked, Loose, and Piked.
MOVE TO THE MATS
Rolling Mechanics Guide Facilitator Guide
Gravity and Rotation Mechanics
Lesson
01
Timeframe
60 Minutes
Equipment
Mats, Lab Reports, Slide Deck
Focus Skill
F/B Rolls, Rotational Velocity
10m
The Hook & Theory
Display the Roll Physics Slides . Discuss the Ice Skater Paradox. Introduce the concept of Angular Momentum and Center of Gravity . Ensure students understand that mass closer to the axis = less resistance to rotation.
Key Question:
"If I have a long stick and a short stick, which one is easier to spin? How does that apply to your body in a roll?"
30m
Lab Execution
Distribute the Rotation Lab Report . Students move to mats to practice forward and backward rolls in variations:
Tucked: Maximal compression, highest velocity.Loose: Higher moment of inertia, slower rotation, often results in "thumping" the floor.Piked: Challenging stability; demonstrates the effect of long limbs on rotational path.
10m
Common Misconceptions
The "Head-Push":
Students often try to push with their head. Correction: Emphasize "Looking at the belly button" to round the spine.
Loss of Momentum:
Opening the tuck too early. Correction: Hold the tuck until feet strike the mat.
10m
Synthesis & Cleanup
Students complete the "Conclusion" section of the Lab Report. Review the concept of Moment of Inertia one last time before dismissal.
Technical Analysis Reference
Biomechanical Principle: Conservation of Angular Momentum
\[ L = I \omega \]
Where \(L\) is angular momentum, \(I\) is moment of inertia, and \(\omega\) is angular velocity. Because \(L\) remains constant in the air (or during the roll initiation after force is applied), decreasing \(I\) (by tucking) forces \(\omega\) (speed) to increase.
Spotting Guide (F. Roll)
Hand at back of neck (guiding tuck).
Hand on thigh/hip to assist rotation.
Ensure chin is pinned to chest.
Spotting Guide (B. Roll)
Lift at hips to take pressure off neck.
Guide feet over the head.
Vertical Alignment Slides Vertical Alignment
Base of Support & Inversion Stability
Unit: Biomechanical Spec | Lesson 02: Inversion Dynamics
The Human Skyscraper
Why can a skyscraper stand hundreds of feet tall without tipping?
Joint Stacking & Center of Mass Management.
In a handstand, you aren't "holding yourself up" with muscle; you are "stacking" your bones.
WRIST
ELBOW
SHOULDR
HIPS
ANKLES
FIG A: VERTICAL STACK
Base of Support (BoS)
Definition
The area beneath an object or person that includes every point of contact that the object or person makes with the supporting surface.
Pro-Tip:
The larger the base of support, the more stable the object. Why is a headstand easier than a handstand?
Small BoS (Handstand)
Large BoS (Headstand Tripod)
The Balance Equation
Equilibrium
Stability is maintained as long as the Line of Gravity (vertical projection of the Center of Mass) remains within the Base of Support .
1
If the CoM moves outside the BoS, you fall.
2
Core tension "locks" the skyscraper so it doesn't buckle.
3
Adjusting fingers = shifting the BoS to "catch" the CoM.
Blueprint Drill
The Tripod
Testing stability with a large base. Analyze the Triangle formation.
The Stack
Wall-supported handstands focusing on the Vertical Line.
DEPLOY TO LAB STATIONS
Balance Blueprint Inversion Blueprint
Project: Vertical Alignment Stability [L-02]
Subject Name
Lab Date
Class Period
1
Mapping the Base of Support (BoS)
In the boxes below, sketch the "footprint" of your contact points with the mat for each position. Shade the area that represents your total Base of Support.
A. Standing (2 Feet)
B. Headstand Tripod
C. Handstand
Analysis:
Rank the positions from Most Stable to Least Stable based on the surface area of your BoS:
1 (Most): __________ 2: __________ 3 (Least): __________
2
The Vertical Stack Challenge
Perform wall-supported handstands. Focus on "stacking" your joints to minimize muscle fatigue. Rate your alignment in the following areas:
Alignment Checkpoint Self-Rating (1-5) Biomechanical Observation Wrists over Palms Shoulders over Wrists Hips over Shoulders Core "Hollow Body" Tension
3
The Edge of Equilibrium
Observation A: Center of Mass Shifting
As you move your hips away from the wall, what happens to the weight distribution in your hands? When do you feel like you are about to tip over?
Observation B: Corrective Forces
How do your fingers act as a "secondary base"? Describe the movement your fingers make when your weight shifts too far toward your back.
Final Synthesis
Explain in 2-3 sentences why "stacking" joints vertically reduces the amount of muscular force (effort) required to hold an inversion.
SPEC: 9.PE.G.02.STABILITY
REF: BIOMECHANICAL_ANALYSIS_V1.0
ENGINEERING THE HUMAN MACHINE
PAGE 02 OF 02
Handstand Facilitator Guide Inversion Guide
Lesson 02: Stability & Alignment
TEACHER RESOURCE
STABILITY_PROTOCOLS_V2
Safety First: The "Bail Out"
Before any free-standing attempts, students MUST learn the Pirouette Exit (turning to one side and stepping down) or the Forward Roll Exit . Never allow students to "bridge" or "backbend" out of a handstand if they lose balance, as this risks spinal injury in novices.
1. Headstand Drills
The Tripod Rule:
Hands and head must form an equilateral triangle. If the head is in line with the hands, the Base of Support is too narrow, leading to instability.
Weight Distribution:
Emphasize 70% weight on hands, 30% on head. This protects the cervical spine and allows for better control.
2. Handstand Drills
The Wall Walk:
Have students walk feet up the wall while facing the wall. This forces Vertical Alignment and prevents the "Banana Back" (anterior pelvic tilt).
Shoulder Blocking:
"Push the floor away." Students should try to close the gap between their shoulders and ears to create a rigid, stable structure.
Biomechanical Spotting Protocols
Location:
Stand to the side of the student. Never stand directly in front or behind the "fall line."
Grip:
Grasp the student at the hips or lower shins. Do not pull; merely provide a "limit" for their momentum.
Focus:
Watch the Center of Mass (Hips) . If the hips stay over the base, the legs will follow.
Socratic Inquiry Prompts
"Why does engaging your glutes and core make you feel 'lighter' in a handstand?" (Answer: Creates a rigid lever/column, reducing energy leaks.)
"Look at your partner's hands. Are they flat or cupped? Which provides a more reactive base of support?" (Answer: Slightly cupped 'spider fingers' allow for micro-adjustments.)
Wheel Motion Slides Wheel Motion
Lateral Dynamics & Angular Momentum
Session 03 // Biomech series
Body as a Lever
Think of your body as a spoke on a wheel.
"The longer the lever, the greater the velocity at the end of the limb."
In a cartwheel, your arms and legs are the levers that transfer your weight from horizontal to vertical and back.
FULCRUM = YOUR HANDS
The Sequential Rhythm
1
Lead Hand
Establishes the initial axis of rotation.
2
Second Hand
Completes the Base of Support for the inversion phase.
3
First Foot
Reaches for the floor to begin weight transfer.
4
Finish Foot
Lands in a lunge to absorb and redirect momentum.
Lateral Power
The cartwheel is not just a circle; it is a vector .
To move smoothly, you must keep your Center of Mass travelling in a straight line relative to the mat.
Hips must square up to the direction of travel.
Eyes look between hands (the target).
Leg extension creates the "Wheel" aesthetic.
Engineering the Arc
Today's goal: Rhythmic Precision .
"Can you make your cartwheel look like a perfectly straight spoke on a wheel, or is your wheel wobbly?"
OPEN LAB: CARTWHEEL STATION
Cartwheel Mechanics Checklist Cartwheel Spec
Biomechanical Integrity Checklist
REF: LATERAL_DYNAMICS_03
DATE: 2026.01.18
Gymnast:
Analyst (Peer):
Technical Evaluation
Movement Phase Biomechanical "Perfect Form" Indicator Achieved? 01. INITIATION Deep Lunge Entry
Front knee over ankle; weight shifts forward to create initial torque.
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| 02. RHYTHM |
Consistent Timing
Even "1-2-3-4" cadence (Hand-Hand-Foot-Foot).
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| 03. INVERSION |
Straight Line Path
Hands and feet land on a single imaginary line (no "arch" or "deviation").
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| 04. LEVERAGE |
Full Extension
Legs pass through a vertical "V" shape at peak height; knees locked.
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Analyst Feedback
Top biomechanical inefficiency observed:
Suggested correction drill:
Gymnast Reflection
How did your momentum feel today?
Mastery Level: 0-100%
Leverage and Lateral Drills Guide Lateral Toolkit
Lesson 03: Levers & Angular Momentum
Session Code LM-03
The Lever Mechanic
Long vs. Short Levers:
"Arms and legs act as third-class levers. In a cartwheel, the force is applied at the shoulder/hip, and the weight (end of limb) travels in a large arc. Longer, straighter limbs create more Linear Velocity at the feet, resulting in a more powerful exit."
Key Variable: Angular Momentum
To keep the "wheel" spinning smoothly, students must maintain a consistent Moment of Inertia . Bent knees "shorten" the lever, decreasing the aesthetic and technical quality of the rotation.
Field Drills
01
The Tightrope Path
Place a 10ft strip of painter's tape on the mat. Students must place both hands and both feet directly on the tape. This enforces lateral alignment and prevents "arching" the body away from the axis.
02
The Wall Shadow
Have students perform cartwheels with their backs nearly touching a wall. If their feet or butt hits the wall, they are losing lateral tension. This drill emphasizes the "thin" nature of the cartwheel plane.
03
The Metronome Kick
Use an actual metronome or a steady clap. Students must hit each contact (H-H-F-F) on a beat. This emphasizes Temporal Precision and prevents "stalling" in the inversion phase.
Troubleshooting the Wheel
The "Wobbly Spoke" (Bent Knees)
Biomechanical Cause: Weak core engagement or fear of inversion, leading to a collapsed lever.
Correction:
"Focus on pushing your toes toward the ceiling. Point your toes to engage the entire posterior chain."
The "Short Circuit" (Hands turned in)
Biomechanical Cause: Incorrect wrist rotation, preventing a smooth lateral transfer of mass.
Correction:
"First hand should point toward the starting side; second hand should point back toward the start. Like turning a steering wheel."
Coaching Cues
"Reach-Kick-Push-Land"
"Hands hide the ears"
"Look for your landing"
Power Snap Slides Power Snap
Round-Off & Momentum Conversion
POWER GEN
LESSON 04
The Great Pivot
A Round-Off is more than a "cartwheel to feet."
It is a MACHINE that converts Horizontal Running Speed into Vertical Rebound Power.
Run Momentum
SNAP DOWN
Vertical Flight
The Hurdle: Phase 01
Biomechanical Purpose
The hurdle (skip entry) prepares the body for a long, powerful step. It lowers the Center of Mass and angles the torso forward for maximum Torque .
"Reach long, not just down. Distance = Time to generate force."
DRIVE THROUGH THE MAT
Shoulder Blocking
THE POP
Newton's 3rd Law
Pushing DOWN against the floor with the shoulders results in an equal force pushing the gymnast UP.
Rigid Structure
If elbows are bent, power is absorbed (lost). Locked arms act as a rigid piston.
The Snap-Down
Aggressively pulling the legs from vertical to the floor creates the rebound force.
Become the Ball
We aren't just tumbling; we are engineering an explosion. Focus on the BLOCK and the SNAP.
STATION: REBOUND TESTING
Rebound Tracker Worksheet Rebound Tracker
Round-Off Power Analysis // L-04
Name:
Date:
01
The Entry Engine (Hurdle)
Experiment with 3 different hurdle lengths. Note how the length of your entry affects your power generation in the final phase.
Short (Tight)
Focus on quick feet.
Power Rating (1-10)
Medium (Balanced)
Focus on extension.
Power Rating (1-10)
Long (Aggressive)
Focus on speed.
Power Rating (1-10)
02
The Blocking Feedback
Have a partner observe your shoulders during the Blocking phase. Check the boxes that describe your form:
Arms fully locked (Rigid Piston)
Shoulders shrug toward ears
Hands strike the mat at 45° angle
Body stays in "hollow" position
03
Rebound Efficiency Log
Attempt # Hurdle Speed (Low/Med/High) Snap-Down Velocity (1-5) Rebound Height (Inches - Est) Attempt 01 Attempt 02 Attempt 03
Scientific Summary
Based on your log, explain the relationship between your hurdle momentum and your final rebound height. Why does a "lazy" hurdle lead to a low rebound?
ID: REBOUND_ANALYSIS_P4
UNIT: TUMBLING_DYNAMICS
PRODUCED BY BIOMECH LABS
9.PE.G.04
Power Snap Teacher Guide Power Mechanics
Lesson 04: Power Generation & Round-Off
Teacher Guide
Spec: Momentum_Conversion_v1.0
Concept: Momentum Conversion
The Round-Off is the primary "engine" for floor tumbling. It utilizes a 1/4 turn to convert forward linear momentum into vertical angular momentum. The efficiency of this conversion depends on the Shoulder Block and the Snap-Down velocity .
Concept: Shoulder Blocking
Newton’s Third Law in action: The gymnast pushes the floor away aggressively through the shoulders. This "blocking" force prevents the arms from absorbing the energy and instead redirects it upward.
Instructional Drills
Drill 1: Handstand Pops
Students kick into a handstand against a wall. Once vertical, they attempt to "pop" their shoulders to lift their hands off the floor for a split second. This teaches the Blocking Mechanic without the complexity of the full round-off.
Drill 2: Snap-Downs from Surface
Students stand on a raised mat (6-12 inches). They perform a cartwheel/round-off entry, focusing on snapping their feet down to the lower mat and immediately rebounding upward. This emphasizes Snap-Down Velocity .
Common Technical Flaws
The "Flat Finish":
Landing with feet too far behind the center of mass, resulting in backward momentum instead of vertical height.
Fix:
"Snap the feet UNDER the hips. Don't let them trail."
Absorbing the Block:
Bent elbows upon hand contact, which "leaks" power into the arms rather than rebounding off the mat.
Fix:
"Think of your arms as steel pillars. No bending!"
Safe Landing Protocol
Soft Knees:
Never land with locked knees; always allow for slight flexion to absorb the force.
Neutral Spine:
Eyes forward upon landing. Looking down causes the spine to round, increasing injury risk.
Total Foot Contact:
Avoid landing only on toes; aim for mid-foot to distribute the load.
Video Feedback Slides RECORDING...
The Critique
Video Analysis & Biomechanical Review
FRAME: 01-24-2026 | LESSON 05
Seeing the Unseen
The human eye can only process so much information in real-time .
Slow-motion video allows us to isolate the "Micro-Moments" where power is either generated or lost.
Angles
Measure joint extension and body lines.
Timing
Observe the rhythm of hand and foot strikes.
The Center of Mass
Trace the path of the hips through space.
The Analyst's Eye
Joint Stacking
Are the wrists, shoulders, and hips aligned during inversions?
Radius of Rotation
How tight is the "tuck" in the rolls? Is there "air" in the pike?
Momentum Path
Does the body travel in a straight line or deviate laterally?
The Project Workflow
1
Capture 3 skills (Roll, Handstand, Round-off)
2
Import into analysis tool (e.g. Hudl, Dartfish, or slow-mo camera)
3
Annotate: Draw lines and mark key frames.
Ready to Analyze?
Your goal is not perfection today; it is Observation.
LAB STATIONS: ON
Final Biomechanical Critique Project Biomechanical Analysis Report
Culminating Performance Project // Lesson 05
ID: PROJECT_FINALE_G9
STATUS: FIELD_DATA_ENTRY
Lead Analyst (Student Name)
Class Period
Submission Date
01. Subject of Analysis
Choose ONE skill from the unit to analyze in depth. Briefly describe your current mastery level of this skill.
Forward/Backward Roll
Handstand Alignment
The Power Round-Off
Self-assessment notes go here...
02. Frame-by-Frame Breakdown
Record your performance and watch it in slow-motion. Select two critical moments (stills) to analyze.
STILL FRAME 01: INITIATION/ENTRY
Biomechanical Observation:
STILL FRAME 02: PEAK HEIGHT/INVERSION
Biomechanical Observation:
03. Inefficiency Identification
Technical Error:
What specifically did you see in the video that was incorrect? (e.g., bent knees, shoulder collapse)
Biomechanical Root Cause:
Why is this an issue in terms of physics? (e.g., increased moment of inertia, lost force conversion)
Correction Strategy:
What drill or coaching cue will fix this in your next practice session?
Executive Summary
Summarize how your understanding of biomechanical principles (levers, center of mass, angular momentum) has changed the way you approach physical movement. Does "thinking" about the physics make you a better gymnast? Why or why not?
REF: BIOMECH_PROJECT_9_PE
SCHOOL: INDIVIDUAL_DUAL_SPORTS_DIV
ANALYSIS COMPLETE
V.1.0 // JAN 2026
