The Constant Force Resistive Exercise Unit (CFREU) as a Device for Maintaining Muscular Strength <ul><li>Paul E. Colosky J...
Outline <ul><li>Objective, specific aim, and hypothesis </li></ul><ul><li>Review of literature </li></ul><ul><li>History o...
Objective <ul><li>To determine if the Constant Force Resistive Exercise Unit (CFREU) can maintain muscle strength (one rep...
Specific Aim and Hypothesis <ul><li>I). Can the CFREU machine maintain muscular strength similar to free weights over 10-w...
Physiological Effects of Spaceflight <ul><li>Cardiovascular deconditioning </li></ul><ul><li>Negative calcium balance </li...
Effects of Spaceflight on the Musculoskeletal System (Skeletal Muscle Atrophy) <ul><li>Effects on strength: </li></ul><ul>...
Effects of Spaceflight on the Musculoskeletal System (Skeletal Muscle Atrophy) <ul><li>Effects on structure : </li></ul><u...
Adapted from Nicogossian et al., 1993
Requirements for exercise countermeasures  ( Johnson Space Center Exercise Physiology Laboratories)(Ruttley, 2000) <ul><li...
History of Exercise Countermeasures in the U. S. Space Program Treadmill -  excellent for cardiovascular conditioning, min...
History of Exercise Countermeasures in the U. S. Space Program Rubber band devices F = k  x Adapted from Designing Resist...
History of Exercise Countermeasures in the U. S. Space Program Penguin suits Adapted from Nicogossian et al., 1993
History of Exercise Countermeasures in the U. S. Space Program Isokinetic Dynamometer Adapted from Nicogossian et al., 1993
History of Exercise Countermeasures in the U. S. Space Program <ul><li>Hydraulic or pneumatic machines </li></ul><ul><li>O...
The Constant Force Resistive Exercise Unit (CFREU) - allows for concentric  and eccentric contractions - full range of mot...
Procedures <ul><li>9 subjects (males and females) </li></ul><ul><li>CFREU (n = 5) and FW (n = 4) groups </li></ul><ul><li>...
Instruments Leg extension/leg curl device configured for free weights . Leg extension/leg curl device configured for CFREU.
Procedures (cont.) <ul><li>One Repetition Maximum Protocol </li></ul><ul><ul><li>Graded 1RM of left leg at W-2, W15, and W...
Data Analysis <ul><li>- Data was analyzed using the statistical analysis computer program SAS.  </li></ul><ul><li>- The al...
Results Percent improvement in 1RM between the CFREU and FW   during leg extension. 31.54 13.66 0.00 10.00 20.00 30.00 40....
Results Percent improvement in 1 RM between the CFREU and   FW during leg flexion. 36.57 7.38 0.00 10.00 20.00 30.00 40.00...
Results 5 Weeks Leg extension/Leg curl performance variables (mean  SD; N = 9) Group CFREU FW Mean SD Increase (%) Mean SD...
Discussion <ul><li>Results of this study reflect overall strength improvements in 1RM for the CFREU and FW groups during l...
Discussion <ul><li>Results of this study reflect overall strength improvements in 1RM for the CFREU and FW groups during l...
Discussion Pre  5 WK  Post 1-Repetition Maximum (kg) 0 10 20 30 40 50 60 Mean (SE) D8855 F2820 M0477 N9336 R7479 Compariso...
Discussion Pre  5 WK  Post 1-Repetition Maximum (Kg) 0 10 20 30 40 50 Comparison of the individual 1RM to pre, 5 wk, &  po...
Discussion Pre  5 WK  Post 1-Repetition Maximum (kg) 0 20 40 60 80 Mean (SE) P2493 P2703 S6020 V4415 Comparison of the ind...
Discussion Pre  5 WK  Post 1-Repetition Maximum (kg) 0 10 20 30 40 50 60 Comparison of the individual 1RM to pre, 5 wk, & ...
Discussion <ul><li>Results of this study reflect overall strength improvements in 1RM for the CFREU and FW groups during l...
 
Discussion <ul><li>Results of this study reflect overall strength improvements in 1RM for the CFREU and FW groups during l...
  CFREU Free Weights Knee angle 45  Knee Knee Ankle Ankle Redirect pulley
T  =  Force  *    Distance Cos     *  Force  =  Effective Force
T  =  Force  *    Distance Cos     *  Force  =  Effective Force
  CFREU Free Weights Knee angle 45 
Conclusions <ul><li>Use of the CFREU to maintain strength resulted in significant increases in 1RM during the 10-week main...
Recommendations <ul><li>Use a free weight machine that is similar to the CFREU configuration (weight stacks operated throu...
Acknowledgements <ul><li>Marvin Criswell, Ph.D. </li></ul><ul><li>Timothy Tong, Ph.D. </li></ul><ul><li>Vinson Sutlive, Ph...
 
Effects of Spaceflight on the Musculoskeletal System (Skeletal Muscle Atrophy) Effects on structure :  slow twitch vs. fas...
Effects of Spaceflight on the Musculoskeletal System (Bone Loss) <ul><li>Bone Loss: </li></ul><ul><ul><li>0-10.1% bone los...
Muscle Response to Exercise <ul><li>Resistance training: </li></ul><ul><ul><li>Muscle hypertrophy/hyperplasia </li></ul></...
 
 
 
 
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EC2ON Masters Thesis

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EC2ON Masters Thesis

  1. 1. The Constant Force Resistive Exercise Unit (CFREU) as a Device for Maintaining Muscular Strength <ul><li>Paul E. Colosky Jr, ATC </li></ul><ul><li>Department of Health and Exercise Science </li></ul><ul><li>Colorado State University </li></ul><ul><li>Fort Collins, CO 80523 </li></ul><ul><li>Master’s Thesis Defense: Spring 2001 </li></ul><ul><li>Committee: Matthew Hickey, Ph.D., Robert Gotshall, Ph.D., Vinson Sutlive, Ph.D., Susan James, Ph.D. </li></ul>
  2. 2. Outline <ul><li>Objective, specific aim, and hypothesis </li></ul><ul><li>Review of literature </li></ul><ul><li>History of Countermeasure </li></ul><ul><li>CFREU description </li></ul><ul><li>Methods and Results </li></ul><ul><li>Conclusions and Recommendations </li></ul>
  3. 3. Objective <ul><li>To determine if the Constant Force Resistive Exercise Unit (CFREU) can maintain muscle strength (one repetition maximum) during a 10-week maintenance program as compared to free weights. </li></ul>
  4. 4. Specific Aim and Hypothesis <ul><li>I). Can the CFREU machine maintain muscular strength similar to free weights over 10-weeks. </li></ul><ul><ul><li>Hypothesis: </li></ul></ul><ul><ul><ul><li>- Strength training exercise performed to maintain muscular strength is as effective using the Constant Force Resistive Exercise Unit as conventional free weights. </li></ul></ul></ul>
  5. 5. Physiological Effects of Spaceflight <ul><li>Cardiovascular deconditioning </li></ul><ul><li>Negative calcium balance </li></ul><ul><li>Decreased plasma volume </li></ul><ul><li>* Musculoskeletal Deconditioning: </li></ul><ul><ul><li>Bone mineral loss </li></ul></ul><ul><ul><li>* Muscle atrophy </li></ul></ul>
  6. 6. Effects of Spaceflight on the Musculoskeletal System (Skeletal Muscle Atrophy) <ul><li>Effects on strength: </li></ul><ul><ul><li>5% weekly reduction in maximal voluntary knee extensor (quadriceps) strength during isometric, concentric and eccentric contractions (Tesch & Berg, 1998). </li></ul></ul><ul><ul><li>Effects have been prevented during bed rest using a combination of endurance and resistance training (Convertino, 1996). </li></ul></ul>
  7. 7. Effects of Spaceflight on the Musculoskeletal System (Skeletal Muscle Atrophy) <ul><li>Effects on structure : </li></ul><ul><ul><li>Using MRI techniques, muscle volume (CSA) changes occur as quickly as 8 days during shuttle missions, with losses of 3.3% for the anterior calf, 2.9% for the posterior calf, 2.5% for the quadriceps, 3.2% for the hamstrings, and 2.0% for the intrinsic back (LeBlanc et al., 1995). </li></ul></ul><ul><ul><li>During 37 days of bed rest the knee extensors lost 15%, which averaged approximately 3% loss per week (Berg et al., 1997). </li></ul></ul>
  8. 8. Adapted from Nicogossian et al., 1993
  9. 9. Requirements for exercise countermeasures ( Johnson Space Center Exercise Physiology Laboratories)(Ruttley, 2000) <ul><li>Ability to allow dynamic eccentric and concentric exercise, ideally with an increased eccentric to concentric ratio. </li></ul><ul><li>Ability to maintain a constant force over an entire exercise range. </li></ul><ul><li>Safe to use, easy to operate, uses no power to operate. </li></ul><ul><li>Design can be used in various gravity environments. </li></ul>
  10. 10. History of Exercise Countermeasures in the U. S. Space Program Treadmill - excellent for cardiovascular conditioning, minimal effect on musculoskeletal system .
  11. 11. History of Exercise Countermeasures in the U. S. Space Program Rubber band devices F = k  x Adapted from Designing Resistance Training Programs, Fleck & Kraemer, 1997.
  12. 12. History of Exercise Countermeasures in the U. S. Space Program Penguin suits Adapted from Nicogossian et al., 1993
  13. 13. History of Exercise Countermeasures in the U. S. Space Program Isokinetic Dynamometer Adapted from Nicogossian et al., 1993
  14. 14. History of Exercise Countermeasures in the U. S. Space Program <ul><li>Hydraulic or pneumatic machines </li></ul><ul><li>Other sci-fi countermeasures </li></ul>
  15. 15. The Constant Force Resistive Exercise Unit (CFREU) - allows for concentric and eccentric contractions - full range of motion - easy weight selection
  16. 16. Procedures <ul><li>9 subjects (males and females) </li></ul><ul><li>CFREU (n = 5) and FW (n = 4) groups </li></ul><ul><li>Workout at 67% pretest 1RM, 3 days/week for 8 - 10 weeks (left leg only) </li></ul>
  17. 17. Instruments Leg extension/leg curl device configured for free weights . Leg extension/leg curl device configured for CFREU.
  18. 18. Procedures (cont.) <ul><li>One Repetition Maximum Protocol </li></ul><ul><ul><li>Graded 1RM of left leg at W-2, W15, and W30 (Kokkonen et al., 1998). </li></ul></ul><ul><ul><li>Lifts were preceded by 10-15 minutes of warm-up and followed with a cool down. Between sets, 3-5 minute rest periods were allowed to decrease the risk for injury. </li></ul></ul>
  19. 19. Data Analysis <ul><li>- Data was analyzed using the statistical analysis computer program SAS. </li></ul><ul><li>- The alpha level chosen for this study is p < .05. </li></ul><ul><li>- For N=9, a repeated measures analysis of variance was used to compare pre, wk 5, and post 1-RM’s. </li></ul>
  20. 20. Results Percent improvement in 1RM between the CFREU and FW during leg extension. 31.54 13.66 0.00 10.00 20.00 30.00 40.00 Groups Percent CFREU FW
  21. 21. Results Percent improvement in 1 RM between the CFREU and FW during leg flexion. 36.57 7.38 0.00 10.00 20.00 30.00 40.00 Groups Percent CFREU FW
  22. 22. Results 5 Weeks Leg extension/Leg curl performance variables (mean SD; N = 9) Group CFREU FW Mean SD Increase (%) Mean SD Increase (%) 1 Repetition Maximum (kg) Leg extension Pre 32.36 5.17 43.60 14.21 5 Weeks 41.21 9.37 27.33 46.43 9.37 6.50 Post 42.57 9.16 3.30 49.55 11.38 6.72 Overall Gains 31.54 13.66 Leg flexion Pre 25.43 3.93 38.40 6.10 34.73 5.22 36.57 42.08 6.55 9.60 Post 34.73 6.96 0.00 41.23 4.38 -2.02 Overall Gains 36.57 7.38 * significantly different (p < 0.05) * * *
  23. 23. Discussion <ul><li>Results of this study reflect overall strength improvements in 1RM for the CFREU and FW groups during leg extension and leg curl exercises </li></ul><ul><li>Possible explanations: </li></ul><ul><ul><li>CFREU may have produced greater resistance than that selected </li></ul></ul>
  24. 24. Discussion <ul><li>Results of this study reflect overall strength improvements in 1RM for the CFREU and FW groups during leg extension and leg curl exercises </li></ul><ul><li>Possible explanations: </li></ul><ul><ul><li>CFREU may have produced greater resistance than that selected </li></ul></ul><ul><ul><li>Subjects in the CFREU group were inherently able to increase muscle strength faster than the FW group </li></ul></ul>
  25. 25. Discussion Pre 5 WK Post 1-Repetition Maximum (kg) 0 10 20 30 40 50 60 Mean (SE) D8855 F2820 M0477 N9336 R7479 Comparison of the individual 1RM to pre, 5 wk, & post training means for leg extension using the CFREU.
  26. 26. Discussion Pre 5 WK Post 1-Repetition Maximum (Kg) 0 10 20 30 40 50 Comparison of the individual 1RM to pre, 5 wk, & post training means for leg flexion using the CFREU . Mean (SE) D8855 F2820 M0477 N9336 R7479
  27. 27. Discussion Pre 5 WK Post 1-Repetition Maximum (kg) 0 20 40 60 80 Mean (SE) P2493 P2703 S6020 V4415 Comparison of the individual 1RM to pre, 5 wk, & post training means for leg extension using FW.
  28. 28. Discussion Pre 5 WK Post 1-Repetition Maximum (kg) 0 10 20 30 40 50 60 Comparison of the individual 1RM to pre, 5 wk, & post training means for leg flexion using FW. Mean (SE) P2493 P2703 S6020 V4415
  29. 29. Discussion <ul><li>Results of this study reflect overall strength improvements in 1RM for the CFREU and FW groups during leg extension and leg curl exercises </li></ul><ul><li>Possible explanations: </li></ul><ul><ul><li>CFREU may have produced greater resistance than that selected </li></ul></ul><ul><ul><li>Subjects in the CFREU group were inherently able to increase muscle strength faster than the FW group </li></ul></ul><ul><ul><li>Test machine specificity </li></ul></ul>
  30. 31. Discussion <ul><li>Results of this study reflect overall strength improvements in 1RM for the CFREU and FW groups during leg extension and leg curl exercises </li></ul><ul><li>Possible explanations: </li></ul><ul><ul><li>CFREU may have produced greater resistance than that selected </li></ul></ul><ul><ul><li>Subjects in the CFREU group were inherently able to increase muscle strength faster than the FW group </li></ul></ul><ul><ul><li>Test machine specificity </li></ul></ul><ul><ul><li>CFREU configuration applies a smaller range of resistive torque on the knee joint compared to FW </li></ul></ul>
  31. 32.   CFREU Free Weights Knee angle 45  Knee Knee Ankle Ankle Redirect pulley
  32. 33. T = Force *  Distance Cos  * Force = Effective Force
  33. 34. T = Force *  Distance Cos  * Force = Effective Force
  34. 35.   CFREU Free Weights Knee angle 45 
  35. 36. Conclusions <ul><li>Use of the CFREU to maintain strength resulted in significant increases in 1RM during the 10-week maintenance program. </li></ul><ul><li>All subjects in the CFREU group showed increases in 1RM at 10-weeks compared to their pre test values illustrating that the device did maintain strength during the course of the study. </li></ul>
  36. 37. Recommendations <ul><li>Use a free weight machine that is similar to the CFREU configuration (weight stacks operated through the same pulley system). </li></ul><ul><li>Extend total time of the study allowing subjects time to adapt to the type of resistance provided by the CFREU. </li></ul><ul><li>Larger sample size may be needed to account for diverse athletic backgrounds. </li></ul><ul><li>Test other exercise configurations </li></ul><ul><li>Test CFREU as a countermeasure for use in microgravity using simulated microgravity (bed rest study). </li></ul>
  37. 38. Acknowledgements <ul><li>Marvin Criswell, Ph.D. </li></ul><ul><li>Timothy Tong, Ph.D. </li></ul><ul><li>Vinson Sutlive, Ph.D. </li></ul><ul><li>M.L. Johnson, Ph.D. </li></ul><ul><li>James zumBrunnen, Ph.D. </li></ul><ul><li>Jonathan Dory </li></ul><ul><li>Maile Ceridon </li></ul><ul><li>John Zentner </li></ul><ul><li>Derek Abbott </li></ul><ul><li>Sarah Driesen </li></ul><ul><li>Tara Ruttley </li></ul><ul><li>Dolores Price </li></ul><ul><li>McNair Scholars Program </li></ul><ul><li>JSC Exercise Physiology Labs </li></ul><ul><li>CSU Sports Medicine </li></ul>* Funded by the CSU Space Grant
  38. 40. Effects of Spaceflight on the Musculoskeletal System (Skeletal Muscle Atrophy) Effects on structure : slow twitch vs. fast twitch Shenkman et al., 1998
  39. 41. Effects of Spaceflight on the Musculoskeletal System (Bone Loss) <ul><li>Bone Loss: </li></ul><ul><ul><li>0-10.1% bone loss in the spine, 1-11% bone loss in the femoral neck, and 0- 9.5% loss in the tibia bone of cosmonauts after long-duration fights > 6 months (Baldwin et al., 1996). </li></ul></ul><ul><ul><li>Bed rest studies have shown 1% bone loss in load bearing muscle (Nicogossian & Pool, 1993). </li></ul></ul>
  40. 42. Muscle Response to Exercise <ul><li>Resistance training: </li></ul><ul><ul><li>Muscle hypertrophy/hyperplasia </li></ul></ul><ul><ul><li>Decrease in mitochondrial density </li></ul></ul><ul><ul><li>Decrease in capillary density </li></ul></ul><ul><li>Endurance training: </li></ul><ul><ul><li>Increase in mitochondrial density </li></ul></ul><ul><ul><li>Increase in capillary density </li></ul></ul><ul><ul><li>Minimal impact on CSA of muscle </li></ul></ul>

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