a pedestal design for the total gym - new york … pedestal design for the total gym revision c 2009...

A Pedestal Design for the Total Gym Revision C 2009 Richard Butts

Richard E. Butts [email protected] @Richard_Butts

http://www.frontiernet.net/~richeb/

Elevate your paddlesport training! December 2009

A Pedestal Design for the Total Gym

mailto:[email protected]

http://www.frontiernet.net/~richeb/

http://www.linkedin.com/pub/richard-butts/19/81a/734


A Pedestal Design for the Total Gym

Contents Project Overview ........................................................................................................................................... 3

Bill of Materials, Tools and Suggestions ....................................................................................................... 5

Pedestal Assembly and Detail Drawings ....................................................................................................... 6

General Views of the Pedestal .................................................................................................................. 6

View of the Pedestal and the Total Gym showing Assembly Details ........................................................ 7

Dimensions of the Base............................................................................................................................. 8

Dimensions of the Angled Support ........................................................................................................... 9

Dimensions of the Top ............................................................................................................................ 10

Dimensions of the Upright ...................................................................................................................... 11

Dimensions of the U-Bolt ........................................................................................................................ 12

Some Close-Up Views of the 2 7/8” x 4” Pedestal and the Platform Weight Bar ........................................ 13

Static Resistance Provided by the Pedestal’s Height .................................................................................. 15

Height & Incline Comparison of the Total Gym 1000 Series and the Total Gym on the Pedestal .......... 15

Graph of the Static Resistance Presented to the User as % of Platform Load and Angle ...................... 16

Examples of Static Resistance vs Platform Load and Angle .................................................................... 16

Calculating the Force and Power Required to do the Prone Push-Down Exercise ..................................... 17

Details of an Example Prone Push-Down ................................................................................................ 17

Diagram of the Platform Forces .............................................................................................................. 17

Equations for Force and Power vs. Time for the Example Prone Push-Down Exercise .......................... 18

Calculating the Force and Power vs. Time from the Platform’s Acceleration and Velocity ................... 19

Power Required Per-Person in Tandem Marathon Canoe Paddling....................................................... 20

Comparison of Power: Example Prone Push-Down Exercise vs. 7 MPH Tandem Marathon Canoe ...... 20

Unintentional but Happy Consequences – The seated, single arm lat pull down ...................................... 21

Appendix A: Photos of the Total Gym 1000 Series Showing Angles and Dimensions ................................ 22


Project Overview The Total Gym 1000 series is a terrific piece of exercise equipment for strengthening the muscles used in

the canoe and kayak paddling motion. It allows a large variety of arm motions and requires engaging the

torso and back while using the arms. Some people using the Total Gym for paddling-related exercises

find that the exercise resistance available in the product is too small. This project provides details of a

pedestal that increases the exercise resistance. The exercise resistance comes from the angle of the

platform and the weight on the platform. Increasing the exercise resistance can be done either by

increasing the platform’s angle so that a larger percent of the user’s weight is lifted or by adding weight

to the platform via attachment of a bar at the bottom edge of the platform for the addition of barbell

plates or by doing both.

Here are drawings and photos of a pedestal I made to increase the platform’s angle and with it the

exercise resistance. Along with the increased height the pedestal also improves the lateral stability by

increasing the width of the base by 68% (from 16” to 27”). I have used this pedestal for about three

years and I found it is stable and rigid. I’m quite happy with it. The motivation for increasing the

platform’s angle via this pedestal is an alternative to the method used by Mr. Marc Gillespie (principal of

Forge Racing). Marc has the upper end of his Total Gym attached to a steel pole in his basement. The

pole is a structural support of the house, is about 4” in diameter and is commonly used in house

construction in this area. My house also has such support poles but there are none in a location

convenient for placing the Total Gym.

The finished pedestal looks like this:

Notice that this pedestal keeps the vertical orientation of the Total Gym’s vertical support. For that to

happen, the bottom end of the diagonal support is kept in nearly its original location relative to the floor

and relative to the axis of the vertical support. In the photo above you can see the diagonal support has

its lower attachment point moved down to the base of the pedestal from its original position on the

Total Gym’s vertical support.

http://www.forgeracing.org/


You are responsible for safety while using the Total Gym and any modifications you make to it. If you

increase the angle of the platform by simply putting the vertical support on top of something such as a

box then the vertical support won’t be vertical and the Total Gym will be unstable and unreliable. Don’t

use the Total Gym in an unstable or unreliable condition. Be aware that increasing the angle of the

platform causes increased load in the hand grips, cables, pulleys and fasteners. You are responsible for

determining that your hand grips, cables, pulleys and fasteners are capable of handling the increased

load before you decide to use them.

The following pages show the materials, tools and parts used for making a pedestal from 4” x 4”

dimensional lumber. What the lumber yards call 4” x 4” dimensional lumber is actually 3 ½” x 3 ½” when

it arrives in the hands of us users. You will see 3 ½” x 3 ½” on all the drawings. The pedestal shown in the

photo is the one I have used for several years and it is made from a large pallet’s stringer which is 2 7/8”

x 4”. In this paper I’ve taken its design and adapted it to the more common 4” x 4” dimensional lumber

size. In case you’re wondering, I have not used 4” x 4” dimensional lumber and these drawings to build a

pedestal. The pedestal I made is from 2 7/8” x 4” lumber. If you find an error, missing dimension or have

a suggestion about this project please contact me.

A person could get the same static resistance increase by adding weight to the platform instead of

increasing the platform angle. Adding about 54% of your body weight to the platform will be statically

equivalent to increasing the platform angle the amount this pedestal affords. I found the standard Total

Gym is too unstable side-to-side when set to its maximum angle and the platform is moved aggressively.

Before I added more weight I wanted to add side-to-side stability. The platform added stability and

static resistance. Adding weight to the platform is a good idea only if the system is stable. The additional

weight requires that you apply additional force to accelerate it. After developing the pedestal I added a

bar and weights to the platform in the same way others have done. A detailed photo of the bar

attachment is at the end of this document.

You’re welcome to use this design for any non-commercial purpose. If you make one, you have the

responsibility for the quality and care with which you make it, the quality and care with which you

attach the Total Gym to it and the suitability of the whole system for any use you put it to.

In the pages after the design details there is an analysis of force and power involved in the prone push-

down exercise. There is also a simple analysis of the power required for a 7 mph tandem canoe.

Together these analyses provide the explanation of why the top hand’s power is critical to maximizing

the canoe speed.

I hope you find this information useful. Enjoy and train safely.

Rich Butts, Mechanical Engineer December 2009

[email protected]

This design is drawn in Sketch-Up v7. If you want the model files, contact me.

If you have a project design that you’d like drawn up or analyzed you’re invited

to contact me with your needs.

---------------------------------------------------------- * * * * * * * ----------------------------------------------------------

mailto:[email protected]


Bill of Materials, Tools and Suggestions Bill of Materials

4” x 4” x 10’ Dimensional Lumber, Qty 1 .............. (9’ 4” is needed, can be made from one 8’ and one 4’)

2” U-bolts, Qty 2 ............................................... (for fastening the vertical upright’s base to the pedestal)

¼” x 3 ½“ Hex Head Lag Screws, Qty 7 ............................................. (for fastening the pedestal together)

¼” I.D. x ¾” O.D. Flat Washers, Qty 11 ................................... (7 for the Lag Screws and 4 for the U-Bolts)

1 ¼” x 1 ¼” Right Angle Braces, Qty 2 .................. (for positioning the lower end of the diagonal support)

1” Wood Screws, Qty 6 .......................................... (for fastening the Right Angle Braces to the pedestal)

Wood Glue, Qty A/R ..................................................... (as required, for fastening the pedestal together)

Tools

Tape Measure

Carpenters Square

1/8” Drill Bit .................................................................................. (pilot holes for the ¼” x 3½” lag screws)

¼” Drill Bit ............................................................................ (clearance holes for the ¼” x 3½” lag screws)

1” Auger Drill Bit ...................... (clearance holes for the 7/16” socket used on the lag screws and U-bolts)

Saw ..................... (Hand, Circular, Table or Band – whatever suits you. I used a hand-held circular saw.)

Drill ..... (I used a battery powered portable for the 1/8” and ¼” drills and a ratchet brace for the 1” drill)

7/16” Socket and Wrench ......................................................... (tightening the lag screws and the U-bolts)

Protractor .................................................................................................................................... (optional)

Suggestions

I have not shown pilot hole locations for the lag screws to screw into. You’ll most likely be using a

hand drill to place all the clearance holes. I suggest using the clearance hole as the template from

which to mark the hole location on the mating piece and then drill the pilot holes.

I have no knowledge about what loads and stresses the Total Gym is capable of handling. I have an

approximately five year old Total Gym and for three years I have used it on the Pedestal without

breaking anything. Your results may be different.

I have my Total Gym/Pedestal on a rug instead of on a potentially slippery hard surface.

About two years ago the Total Gym designers, efi Sports Medicine, Inc., changed the handle and cable

attachment design from plastic to metal. At that time Total Gym owners could get the new design at

no cost if they asked for it. I don’t know all the reasons for the design change. Strength and reliability

could be reasons. You might want to update.

Back To Table of Contents

http://www.efisportsmedicine.com/


Pedestal Assembly and Detail Drawings

General Views of the Pedestal

FRONT BACK



View of the Pedestal and the Total Gym showing Assembly Details



Dimensions of the Base


Section A View of

Clearance Holes

Diameter ¼”

Diameter 1”

A


Dimensions of the Angled Support



Dimensions of the Top


Section B View of

Clearance Holes

Diameter ¼”

Diameter 1”

Section A View of

Clearance Holes

Diameter ¼”

Diameter 1”

A

B

Check your U-bolt

center-to-center

distance before

drilling these holes. I

notice the bolt

distance varies about

1/8”

These holes are for the U-Bolts.

See the notes on the U-Bolt

dimensions page before drilling.


Dimensions of the Upright



Dimensions of the U-Bolt

Oddly enough, a 2” U-Bolt is intended to be used on a 1 ½“ pipe!

If your U-Bolt comes with a flat plate, just remove it. It doesn’t get used.

Height of the bolt varies with manufacturer.

Typical height is 3" or 3 ½".

The drawing for the TOP gives ½” of thread

for the nut if you have a 3” bolt. And the bolt

will be clamping 1” of wood.

If you have a 3 ½” bolt you might want to

clamp 1 ½” of wood by shortening the depth

of the four 1” diameter holes to 2”.


Some Close-Up Views of the 2 7/8” x 4” Pedestal and the Platform Weight Bar

The three attachment points of the Total Gym’s vertical upright to the Pedestal - Two U-bolts at the base. One lag screw

through an existing hole in the Total Gym’s vertical upright. Use the hole located about

13” up from the base of the Total Gym.

Bottom view of the recessed U-bolt’s fasteners

Attachment of the diagonal support to the pedestal


Bottom View of Platform Showing Attachment of Additional Bar for Barbell Plates

Back View of Pedestal


Static Resistance Provided by the Pedestal’s Height

The resistance of the Total Gym, like all free weights, has two components – the static resistance and the dynamic resistance.

Static Resistance

The static resistance is the force required to hold the platform load in any position. The static resistance is determined by the

platform load and the platform angle.

Dynamic Resistance

The dynamic resistance is the force required to accelerate the platform load. The dynamic resistance is determined by the total

moving mass and the acceleration of that mass caused by the user’s applied force.

The static resistance is the minimum force the user will experience; the dynamic resistance is determined by the user’s effort; and the sum

of them is the total resistance experienced by the user.

Height & Incline Comparison of the Total Gym 1000 Series and the Total Gym on the Pedestal

Total Gym 1000 Series Total Gym on Pedestal

Platform’s Guide Rail Length 89” Platform’s Guide Rail Length 89”

Guide Rail’s Lowest Height 10 1/4” Rail’s Incline: 6.6 Guide Rail’s Lowest Height 42” Rail’s Incline: 28.2

Guide Rail’s Highest Height 37 7/8” Rail’s Incline: 25.2 Guide Rail’s Highest Height 58 1/4” Rail’s Incline: 40.9

Photos in appendix A were made while gathering these dimensions.


Graph of the Static Resistance Presented to the User as % of Platform Load and Angle

Examples of Static Resistance vs Platform Load and Angle

User’s Weight (Lbs) Additional Weight (Lbs) Total Weight (Lbs) Platform Angle () Static Resistance (Lbs)

=Sin(Platform Angle) x Total Weight

160 0 160 38.1 99

160 40 200 38.1 123

185 0 185 40.9 121

185 50 235 40.9 154


0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90

% o

f P

latf

orm

Lo

ad P

rese

nte

d t

o U

ser

as S

tati

c R

esi

stan

ce

Platform Angle, Degrees

Static Resistance Presented to User as % of Platform Load and Platform Angle

Resistance as % of Platform Load= Sin(Angle)*100%

On

Ped

esta

l: H

igh

est

On

Ped

esta

l: Lo

we

st

Stan

dar

d: H

igh

est

Stan

dar

d: L

ow

est

Use of the pedestal increases the maximum static resistance by

54%. Raising it from the standard’s maximum at 43% of

platform load to the w/pedestal’s maximum at 65% of the

platform load.


Calculating the Force and Power Required to do the Prone Push-Down Exercise The motion of the prone push-down exercise is very similar to the top hand motion of the canoe stroke. That similarity makes it great for training. It is

possible to calculate how much force and how much power are used to do this exercise. The calculated power can be thought of as the top hand’s

potential for propelling a canoe. Many people advocate the top hand’s

power to be critical in developing canoe speed. That thought leads to

asking: At a given speed of a tandem canoe, what percentage of the

required per-person power is equal to the top hand’s power potential? In

the next few pages I’ll develop an answer to that question and the

question of force needed to do this exercise.

For starting out, here is a list of the information I know:

Details of an Example Prone Push-Down

Diagram of the Platform Forces Here is a simple diagram of the platform and the forces acting on it:

Angle of Platform 38.1 degrees

User’s Weight 160.0 lbs

Added Platform Weight 40.0 lbs

Platform Travel (observation) 18.5 inches

Platform Starting Speed (at the bottom) 0.0 in/s

Platform Ending Speed (at the top) 0.0 in/s

Travel Time, bottom to top (observation) 0.5 Seconds

Acceleration due to Gravity 386.4 in/s2

1) Push Down

2) Platform Moves Up

Prone Push-Down Exercise on a Total Gym with Pedestal and Additional Platform Weight

Total Platform Mass x Acceleration due to Gravity = Force of Gravity

MTotal x g =Fgravity

38.1

Applied Force as Function of Time = F(t)


Equations for Force and Power vs. Time for the Example Prone Push-Down Exercise I want to know what the applied force is as a function of time. There are only two forces that act along the platform’s line of travel. Those are the

applied force and a portion of the force of gravity. Notice that they act in opposite directions, so we can call the direction of the applied force

“positive” and the direction of the portion of the gravity force that acts along the platform’s line of travel “negative”. Let Mtotal represent the total

mass on the platform and g represent the vertical acceleration due to gravity. The portion of the force of gravity that is acting along the platform’s

line of travel is equal to Cosine(90-38.1) x Mtotal x g. Since the cosine and the sine are 90 apart we can write that as sin(38.1) x Mtotal x g. Sir Isaac

Newton pointed out that the sum of all the forces acting on a body and along any one line of action equals the time rate of change of the body’s

momentum (momentum equals mass x velocity) along that line of action. That’s the long way of saying the familiar and simplified “F = ma”. Putting

all that together gets us an equation for the force that the user applies to the platform as a function of time and the acceleration that it gives to the

platform as a function of time:

We can also calculate the power as a function of time by knowing that mechanical power is force multiplied by velocity.

Since we want to know the force as a function of time, we must figure out the acceleration as a function of time. And since we want to know the

power as a function of time, we must know the velocity as a function of time. Fortunately for us the acceleration is related to the velocity:

acceleration is the time rate of change of velocity. So if we know or can estimate the velocity as a function of time, then we can know the force and

power as a function of time. Instead of measuring the velocity vs. time, I will estimate it based on experience from doing the exercise. When doing

this exercise it is noticeable that the platform velocity increases to a peak just before the top. Then it slows quickly to a stop at the top. The force is

large and increasing at the start of the motion. Then it quickly drops to what feels like zero just before the top. Then it quickly rises again at the top of

the travel. From those observations I believe the platform’s velocity vs. time is close to a skewed parabola: a nice smooth velocity vs. time curve that

starts at zero going slowly up to a peak then going quickly back to zero. We can use that observation and the other facts we know to calculate an

estimate of the force vs. time and the power vs. time.

*This is the familiar “F=ma” and the Greek

letter sigma,, means “sum of the…”+


Calculating the Force and Power vs. Time from the Platform’s Acceleration and Velocity

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

0.0 0.1 0.2 0.3 0.4 0.5

Vel

oci

ty (

inch

es/s

eco

nd

)

Time (Seconds)

Velocity Along Rail vs Time

0.0

5.0

10.0

15.0

20.0

0.0 0.1 0.2 0.3 0.4 0.5

Dis

pla

cem

ent

(in

ches

)

Time (Seconds)

Displacement Along Rail vs Time

-900.0-750.0-600.0-450.0-300.0-150.0

0.0150.0300.0

0.0 0.1 0.2 0.3 0.4 0.5

Acc

eler

ati

on

(in

ches

/sec

on

d^

2)

Time (Seconds)

Acceleration Along Rail vs Time

Based on experience from doing the prone

push-down exercise this is an estimate of the

velocity vs. time: a skewed parabola.

v(t) = -3552t3+1776t2

This displacement vs. time is the integral of the

velocity vs. time equation and it fits the known

fact of 18.5” travel in 0.5 seconds.

This acceleration vs. time is the derivative of the

velocity vs. time equation.

a(t) = -10656t2+3552t

-100.0

-50.0

0.0

50.0

100.0

150.0

200.0

250.0

300.0

0.0 0.1 0.2 0.3 0.4 0.5

Fo

rce

(Lb

s)

Time (Seconds)

Force Applied to Platform vs Time

0.0

0.5

1.0

1.5

2.0

0.0 0.1 0.2 0.3 0.4 0.5

Po

wer (

H.P

.)

Time (Seconds)

Power Applied to Platform vs

Time

Average Two Arm Power

AverageOne Arm Power

The average one-arm

power is 0.4 HP

The peak force is 275 Lbs

which is 2.2x the static

force of 123 Lbs.


Power Required Per-Person in Tandem Marathon Canoe Paddling How much power does it take to paddle a tandem marathon canoe? Suppose it takes an average, continuous force of 50 Lbs1 to propel a canoe at 7

mph. 7 mph equals 10.3 ft/s. In linear motion, power is force x velocity so the average power is 50 Lbs x 10.3 ft/s = 515 ft-Lbs/s. Converting to Horse

Power, 515 ft-Lbs/s 550 ft-Lbs/s per H.P. = 0.9 H.P. per 2 people. So it requires about 0.5 H.P. per paddler to travel at 7 mph.

1 50 Lbs is very likely to be at the high end of the actual force required to overcome friction drag and wave drag in deep, calm water.

Comparison of Power: Example Prone Push-Down Exercise vs. 7 MPH Tandem Marathon Canoe Analysis of the example for the prone push-down exercise gave us a result of 0.4 H.P. as the average power from one arm.

Recall that the motion of the prone push-down exercise is very similar to the top hand motion of the canoe stroke.

Analysis of the example for paddling a tandem marathon canoe at 7 mph gave us a result of 0.5 H. P. required per paddler.

Conclusion: The top hand in the canoe stroke is capable of producing a large portion of the power required from a paddler in a tandem canoe.

This simple analysis lends support to what many marathon canoe paddlers already know - effectively using the power of the top hand is

a critical ingredient to maximize the canoe speed.

Knowing that effective use of the top hand’s power is critical to maximizing the canoe speed leads to the question - What conditions

enable effective use of the top hand’s power?

1. The top hand must be directly above the blade for the entire duration of the power stroke.

2. The blade must remain at a fixed distance (laterally) from the canoe’s keel for the entire duration of the power stroke.

3. The blade must be fully submerged and perpendicular to the canoe’s keel for the entire duration of the power stroke.

In practice it means – When the catch* occurs, the top hand must already be directly over the blade and it must immediately begin

powering the canoe forward, continuing until the end of the power stroke.

* The catch is that moment at the end of the recovery phase when the blade is quickly and fully submerged. It is the start of the power

stroke.

Comment: This comparison makes the implicit assumption that the power expended in one rep. of the prone push-down exercise can be repeated

for each of the many, many strokes of paddling a canoe. That is not likely to be true. Perhaps 1/3 to 1/2 of the calculated power could be

sustained. Also in calculating the power required to propel the canoe, the force used is likely at the high end of the actual requirement

which may be between 30 to 50 Lbs. Even considering these reductions, the conclusion stays the same.


Unintentional and Happy Consequences – The seated, single arm lat pull down The pedestal has made possible doing a seated, single arm lat pull down. It is easy to reach up and pull down on one of the handles while sitting on a

low seat opposite the Total Gym’s platform. To replicate the top arm’s paddling motion just take your arm across your body and grab the handle then

press it straight down keeping your knuckles pointed forward. Holding onto a loop of rope that is around your foot will position your bottom hand

approximately at the start-of-stroke location. When the total gym was at its factory height the handles were a little too low and the base was not

wide enough to be stable during this exercise. To make this motion useful for training you should have additional weight added to the platform. One

way to do that is with the addition of a bar to the platform and barbell plates as shown earlier in this document. Here are a few photos that show the

arrangement and motion. Notice that my right hand is pulling the handle down on my left side and outboard of my left leg.


Appendix A: Photos of the Total Gym 1000 Series Showing Angles and Dimensions

Total Gym 1000 Series: Highest Position – General View Total Gym 1000 Series: Highest Position – Rail Height

Total Gym 1000 Series: Lowest Position – General View Total Gym 1000 Series: Lowest Position – Rail Height


Total Gym 1000 Series: Diagonal Support Attachment Height Total Gym 1000 Series: Platform Rail Length

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