RSPT 572 Supervisor: Dr. Darlene Reid Teryn Buna, Jonathan Coelho, Kyle Freedman,

1. Does respiratory muscle training improve performance in high level athletes?A Systematic Review and Meta-Analysis RSPT 572 Supervisor: Dr. Darlene Reid Teryn Buna, Jonathan Coelho, Kyle Freedman, Trevor Morton, Sheree Palmer, Melissa Toy, Cody Walsh

2. Outline • Background • Objective • Methods • Results • Discussion • Conclusions • Implications & Future Directions

3. Background

4. Overview • Competition drives top athletes to seek new ways to gain an edge • Top athletes thought to have plateaued their ability to improve: • Muscular function Performance • Cardiovascular function • The role of inspiratory muscles (IM) have recently become a point of consideration in exercise performance research

5. Respiratory System and Exercise Performance • Traditional • Untrained, healthy respiratory system not a performance limiting factor 1, 3, 4 • Supported by no change in VO2max and lactate thresholds following IMT 2,3 • Focus on O2 transport chain • Current • Systemic physiological changes secondary to inspiratory muscle fatigue (IMF)

6. Respiratory System and Exercise Performance • IMF occurs 2° to demands of work of breathing in 3-12 • Marathon running • Rowing • Triathlon • Cycling • Swimming

7. Respiratory System and Exercise Performance • IMF effect on performance • Rating of perceived breathlessness (RPB) 3 • Rating of perceived effort (RPE) 15,16 • Metaboreflex phenomenon • Redirection of blood flow from the periphery to fatiguing IM 13,14 • Can inspiratory muscle training (IMT) have an impact on performance?

8. IMT and Performance • Debate exists whether IMT can positively contribute to performance • 3 areas of inconsistency: • Reliable and valid methods for measuring ‘performance’ • Variety of IMT protocols and training modalities • Types of athletic performance and level of competition

9. Tlim vs. TT 3,15,25,31,32

10. Other study measures

11. IMT Protocols • Types of IMT modalities 25 • Voluntary Normocapnic Hyperpnea (VNH) • Flow Resistive Loading (FRL) • Pressure Threshold Loading (PTL) • Type of IMT protocol chosen based on 25 • Type of adaptations desired • Factors related to time, cost and ease of use No current gold standard

12. Athletic Populations • Studies have examined four main types of athletes • Cyclists, rowers and running athletes may  TT with IMT 9,27,30 • Swimming may not be as sensitive to IMT 1 Lack of consistent results between and within athletic disciplines

13. IMT Literature • Other literature on IMT • Systematic Reviews of COPD and Cystic Fibrosis 45,47 • Favourable results • IMT as an effective adjunct to general exercise • 3 narrative reviews of IMT in healthy and athletic populations 3,15,25 • No systematic or statistical analysis Identified a need in the literature for a systematic review of IMT and performance in high level athletes

14. Objective

15. Objective To conduct a thorough evaluation of the literature and attempt to answer the following questions pertaining to high level athletes: Primary Objective Does IMT improve performance ? Secondary Objectives Does IMT improve IM function ? Which type of athletes or sports benefit most from IMT?

16. Methods

17. PICO

18. Operational Definitions Inspiratory Muscle Training (IMT): an intervention that used either a VNH, FRL or PTL Healthy: fully able-bodied humans, non-injured and without chronic disease High level: an athlete competing at a varsity, national, international or professional level, OR has a VO2max level designated by Wilmore and Costill, 2005

19. VO2 max

20. Search Strategy

21. Search Strategy • Following procedures performed by 2 independent reviewers • Article screening • Title and abstract screening • Screening tool • Inclusion/exclusion criteria • Quality assessment • PEDro scale + • Oxford Level of Evidence + • van Tulder • Data abstraction • Third party reviewer was used when required

22. Study Inclusion • Articles were included if: (1) Participants were high level, healthy athletes (mean age of 18-40 years) (2) Compared IMT to another comparison group (3) An RCT or crossover study design (4) Includes measures of respiratory muscle adaptation with reliable and valid outcome measures (5) English

23. Included Studies • 14 articles • Note: Romer et al, 2002A and Romer et al, 2002B same study data • Sports • Cycling • Endurance running • Intermittent sprint: Soccer, Rugby, Field Hockey, Basketball • Rowing • Swimming

24. Quality Assessment

25. Meta-Analysis • RevMan 5.0.24 for meta-analyses48 • Randomized effects model: • Does not assume a common treatment effect exists • Allows for variation by assuming that effects follow a distribution across all studies • Standardized mean differences: Summary statistic when the studies assess the same outcome but measure it in variety of ways • Used to standardize to a uniform scale • Express the size of the intervention effect relative to the variability observed • Equivalent of ‘effect size’ in social science studies

26. Meta-Analysis • RevMan 5.0.24 48 • Heterogeneity: The extent to which the results of studies are consistent • I2: assesses whether observed differences in results are compatible with chance alone • P <0.1 was considered significant for heterogeneity

27. Meta-Analysis • Analysis done on primary and secondary outcomes • Sport based sub-group analysis was performed • Cycling • Endurance Running • Intermittent Sprint (Soccer, Rugby, Field Hockey, Basketball) • Rowing • Swimming

28. Results

29. Primary Outcomes

30. Primary Outcomes

31. Swimming Intermittent Sprint Sports Figure 1: Meta-analysis results comparing targeted or threshold resistive IMT versus sham or control in whole body athletic performance Cycling Rowing Special Forces Overall Performance Favours IMT Favours control/sham

32. Secondary Outcomes (#) = the number of studies that mentioned the outcome but did not provide numerical data

33. Secondary Outcomes

34. Discussion

35. Summary of Findings • Primary Outcome: • Overall = Meta- analysis found that IMT does have an ergogenic effect on performance Sport based sub-group analysis revealed…. Not all sports are equal! • Intermittent sprint sports and cycling benefited from IMT performance • Swimming, rowing and endurance running were not found to benefit

36. Discussion • Significance of Primary Outcomes • IMT could be used as an adjunct to regular training to enhance performance in high-level athletes • Only in certain sports disciplines

37. Discussion • Secondary Outcomes • Improvements in PImax and MVV across all studies • Improvements in RPB across all studies • Significance • Highly trained athletes are able to improve their IM function • All protocols effective in eliciting training effect • Attenuation of dyspnea is supported as a response to improvements in IM function

38. Discussion • Improvement in performance with cycling and intermittent sprint sports • Correlated with • PImax and MVV • Reduction in RPB

39. Discussion Why does this not translate to rowing, swimming and endurance running performances? • Rowing 9,52 • Dual function of IM = stabilization of the thorax + ventilation • “Entrained” breathing • Different ventilatory mechanics and IM physiological demands • ? Negate or confound IMT related improvements?

40. Discussion Why does this not translate to rowing, swimming and endurance running performances? • Swimming 3,33,50 • Respond with smaller  in PImax following IMT interventions • IM trained by water submersion • Swimmer IM already near function plateau • Unable to gain performance effects from IMT

41. Discussion Why does this not translate to rowing, swimming and endurance running performances? • Endurance Runners 51 • German Special Forces = Not elite athletes within a specific sporting discipline • ‘Generalist’ characteristics + non-specific performance test

42. Discussion Why does this not translate to rowing, swimming and endurance running performances? • Individual characteristics • Each athlete limited by different physiologic or psychologic factors • Some may be more limited by IM function than others • Mix of responders and non-responders within a small sample could affect the effect size

43. Discussion • Individual characteristics • Highlights the need to consider the unique characteristics of each athlete prior to choosing a training intervention

44. Discussion • Other secondary measures • FEV1 • VO2 max • Blood lactate • RPE • Consistent with the literature • FEV1 limited by airway diameter not IM strength • VO2 max does not respond to IMT • Blood lactate postulated to decrease • More recent studies have failed to support this argument

45. Discussion • Lack of positive RPE findings contrasts current literature • Data analyzed on end of test measures • RPE  post IMT for similar workouts during incremental testing • Future studies should examine exercise performance measures during fixed workload tasks vs. end-points of exercise performance

46. Limitations • Small number of studies with sample sizes • Definition of “high-level” athletes • Data abstracted graphs via hand and ruler measurements • McMahon (2002) removed from the analysis • Data could not be reliably extracted from the graph • Attempts to contact the author failed

47. Conclusion

48. Conclusion • IMT improves performance in intermittent sprint and cycling NOT rowing, swimming or endurance running • Where IM serve a dual function (rowing) or already stimulated with regular training (swimming) may not benefit vs. sports in which the sole function of the RM is ventilation • High level athletes able to  IM function with IMT • Can translate into performance improvements • Limited strength of claim

49. Implications • Consider IMT as a possible adjunct to regular athletic training • It is cheap and time effective • Must consider the individual characteristics • Must consider type of athletic performance

50. Future Direction • Call for more, higher quality studies • Studies should examine: • Most effective IMT protocols • Specific sport • Apply IMT in a non-research/field setting with a team/athletic group to determine feasibility and adherence