Advances in Cross-training: Deep Water & Antigravity Treadmill Running for Injury Prevention

1. Advances in Cross-training:The Role of Deep Water & Antigravity Treadmill Running to Prevent Running Injuries Mark A. Harrast, M.D. Medical Director, Sports Medicine Center at Husky Stadium Director, PM&R Sports Medicine Fellowship Medical Director, Seattle Marathon Clinical Professor University of Washington

2. I have nothing to disclose.

3. Objectives Introduce two sport-specific cross training methods: Deep Water Running (DWR) Antigravity Treadmill Training (ATT) Understand the physiology, biomechanics, and performance-related research re these methods Keep it practical

4. Effective Cross-training Training pattern equivalent intensity & duration to original exercise mode Replicate the ROM and muscle recruitment patterns

5. Forms of Cross-training(for the runner) Swimming Cycling Elliptical Deep Water Running (DWR) Anti-gravity treadmill training (ATT)

6. Deep Water Running Running in the deep end of a pool/diving well while wearing a flotation device

7. Buoyancy In order to float in water, SG<1.0. Fat ~0.8 Muscle ~1.0 Bone ~1.5-2.0

8. Wear a flotation device Assists in achieving appropriate running mechanics Most useful for lean body types (without it, mechanics resemble treading water or stair stepping) Max effectiveness: Worn near center of mass Increased ease of breathing by maintaining head position at neutral

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10. Physiologic Parameters of DWR & Treadmill Running Heart rate VO2 Substrate utilization Muscle fiber type

11. Heart RateDWR < treadmill running Water immersion below thermoneutral temp: peripheral vasoconstriction  central blood volume  SV & HR to maintain CO Stimulation of skin cold receptors  vagal activity

12. VO2 MaxDWR < treadmill running Higher in those with previous running experience(& possible better mechanics) Still adequate for training and CV fitness • Reduced VO2 Max: a) water temp  muscle temps  slows muscle enzyme activity b) Muscle recruitment pattern differences i. Smaller muscle mass of upper body used ii. Calves are used less (no push off) iii. No antigravity muscle use since buoyant in water

13. Treadmill DWR VO2 Max 53.1-67.0 46.8-58.4 Max HR 183-198 157-180 Differences in Physiologic Parameters Nine Studies (8-20 athletes) Reilly, J Sports Sci 2003

14. ADAPTATION - training effect Is there a difference between experienced & novice runners? In more experienced runners: 1. Submax VO2, VO2Max, and HR are similar btwn DWR & TMR 2. Possibly due to increased leg muscle recruitment and better adaptation to running form in the water Azevedo 2010 J Sports Sci Kilding 2007 J Strength Cond Res

15. limited research DWR Technique Kilgore 2011 Coaching Athletics Quarterly; Kilgore 2012 Phys & Sports Med 40 (1): 116-26.

16. Guiding Training Intensity:Rating of Perceived Exertion 1-3 points higher in DWR > TMR Perception of work needs to be harder to get the same metabolic (training) effect

17. Training Effect / Performance 4-8 week DWR programs, athletes maintained: VO2max Anaerobic threshold Land running economy Leg strength 2 mile and 5K run performance Bushman, Med Sci Sport Exerc 1997 Wilbur, Med Sci Sport Exerc 1996 Eyestone, A J Sport Med 1993 Hertler, Med Sci Sport Exerc 1992 McKenzie, Clin J Sport Med 1991

18. Can you do better than maintain? 8 week DWR program of progressive interval training VO2Max 2 mile run performance Quinn 1994 Michaud 1995

19. Training Tips Don’t just transmit land workouts to the pool Higher percentage of DWR sessions should be at a harder effort (due to the RPE effect and performance studies) a) Include intervals, tempo, and fartlek training to maintain fitness b) Limit steady state effort runs (not hard enough to maintain fitness) Sample training programs: Liem, Truswell, Harrast 2013 Curr Sports Med Reports 12(3):200-7. Pete Pfitzinger, MS: Kemibe.com/distancecoach/labreports/water.shtml Kemibe.com/distancecoach/labreports/9wkH2O.htm

20. DWR Summary:Practical Recommendations Gradual familiarization is important since mechanics are somewhat different. Wear a flotation device. More interval training (harder workouts) DWR demonstrates a training effect, at a minimum, to maintain, but also potentially improveperformance.

21. Antigravity Treadmill Training (ATT) Designed by NASA engineers Internal scale/force plate Air-filled pressure controlled chamber Unweighting from 100%BW  20%BW (in 1% increments) Used for rehab as well as training

23. Accuracy of Unloading (Body Weight %) McNeill 2015 J Strength & Conditioning R

24. Guiding Training Intensity 3. Conversion table of speeds at different BW% to get the same metabolic demand as TMR. (increase speed to get the same training effect with decreased BW%) HR – the same btwn ATT and TM RPE – similar btwn ATT and TM McNeill 2015 J Sports Sci & Medicine Hoffman 2011 Arch PMR Kline 2015 J Strength & Conditioning R

25. Conversion Table Kline 2015 J Strength & Conditioning R

26. vGRF with Lower BW% Decreases (but not proportionally) Faster speeds drop > slower speeds Biomechanics vGRF on Land & AT Increases with increasing speed Levels off at higher speeds Can run at a similar VO2 with significant less vGRF by lowering BW% and increasing speed Raffalt 2013 Res Q Exercise & Sport

27. Contour plots of impact peak, active peak, &vertical loading rate Grabowski 2008 J Applied Biomechanics 24:288-97.

28. Heel Striker Forces Mid-foot Striker Forces

29. Grabowski 2008 J Applied Biomechanics 24:288-97.

30. Training Tips For healthy runners: Keep BW% (85-95%) and speeds high to normalize motor patterns (most sport specific) Supplement land running with HIIT or faster paced intervals/tempo runs on AT

31. Training Tips For healthy runners: Keep BW% (85-95%) and speeds high to normalize motor patterns (most sport specific) Supplement land running with HIIT or faster paced intervals/tempo runs on AT For injured runners: Start at 50-65%BW (determine what is acceptable, ie no pain) Stay there for ~ 1 week (minimum) Increase 5-10%BW increments weekly No pain during or after running Move to land running after comfortable at 90-95%BW

32. Training Tips For healthy runners: Keep BW% (85-95%) and speeds high to normalize motor patterns (most sport specific) Supplement land running with HIIT or faster paced intervals/tempo runs on AT For injured runners: Start at 50-65%BW (determine what is acceptable, ie no pain) Stay there for ~ 1 week (minimum) Increase 5-10%BW increments weekly No pain during or after running Move to land running after comfortable at 90-95%BW Land based training can be transferred to ATT (unlike DWR)

33. Training Tips For healthy runners: Keep BW% (85-95%) and speeds high to normalize motor patterns (most sport specific) Supplement land running with HIIT or faster paced intervals/tempo runs on AT For injured runners: Start at 50-65%BW (determine what is acceptable, ie no pain) Stay there for ~ 1 week (minimum) Increase 5-10%BW increments weekly No pain during or after running Move to land running after comfortable at 90-95%BW Land based training can be transferred to ATT (unlike DWR) Consider using a metronome to focus on cadence

34. ATT Summary:Necessary future research What are the long term effects of training at a higher speed and lower weight? The relationship btwn BW reduction and GRF’s remains to be better defined. What is the ideal amount of weight support to rehab various diagnoses (stress fractures, post-op achilles tendon surgeries, etc)? How quickly can one advance their weight support? For injury prevention, what are ideal parameters of weight support and speed for a predetermined metabolic workload (but to keep vGRF’s down)? Optimal training methods? (HIIT/supramaximal speeds?)

35. Thank you