Training The Inspiratory Muscles Improves Running Performance When Carrying A 25kg Thoracic Load In A Backpack

“Load carriage (LC) exercise in physically demanding occupations is typically characterised by periods of low-intensity steady-state exercise and short duration, high-intensity exercise while carrying an external mass in a backpack; this form of exercise is also known as LC exercise. This induces inspiratory muscle fatigue and reduces whole-body performance. Accordingly we investigated the effect of inspiratory muscle training (IMT, 50% maximal inspiratory muscle pressure (PImax) twice daily for six week) upon running time-trial performance with thoracic LC.”

Conclusion:

“In summary, when wearing a 25 kg backpack, IMT attenuated the cardiovascular and perceptual responses to steady-state exercise and improved high-intensity time-trial performance which we attribute in part to reduced relative work intensity of the inspiratory muscles due to improved inspiratory muscle strength. These findings have real-world implications for occupational contexts.”

Read Training the inspiratory muscles improves running performance when carrying a 25 kg thoracic load in a backpack >

Respiratory-Related Limitations In Physically Demanding Occupations

“Respiratory muscle work limits high-intensity exercise tolerance in healthy human beings… In an occupational setting, heavy loads are routinely carried upon the trunk in the form of body armour, backpacks, and/or compressed air cylinders by military, emergency service, and mountain rescue personnel. This personal and respiratory protective equipment impairs respiratory muscle function and increases respiratory muscle work.”

Conclusion:

“An argument is presented that the unique respiratory challenges encountered in some occupational settings require further research, since these may affect the operational effectiveness and the health and safety of personnel working in physically demanding occupations.”

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Influence Of Body Armour On Pulmonary Function

“The purpose of the present study was to determine if lightweight body armour (weighing less than 10 kg) would influence pulmonary function in a manner similar to that reported previously for backpacks and heavily weighted jackets.”

Conclusion:

“…a reduction of 10-4% in the maximum voluntary ventilation sustained for 15 s observed in the lightest of the three types of body armour suggests that tightness of fit may be important. The practical consequences of these findings are minimal whilst a person is inactive, but may assume increasing importance when body armour is combined with backpack load carriage during sustained aerobic exercise.”

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Rib Cage And Abdominal Restrictions Have Different Effects On Lung Mechanics

“The effects of a variety of restrictive procedures on lung mechanics were studied in eight healthy subjects.”

Conclusion:

“Lung volume restriction induces changes in lung function, but the nature of these changes depends on how the restriction is applied and therefore cannot be ascribed to low lung volume breathing per se.”

Protective equipment that restricts lung function can increase breathing effort and reduce operational performance. POWERbreathe Inspiratory Muscle Training reverses these impairments.

Read Rib cage and abdominal restrictions have different effects on lung mechanics >

The Effect Of Football Shoulder Pads On Pulmonary Function

“Restriction of expansion of the lungs or chest wall impedes inflation of the lungs during inhalation. Functional changes occurring during such restriction include reduced pulmonary and/or chest wall compliance, decreases in pulmonary function, and ultimately a decrease in exercise performance. Such restriction can be seen in several pathologic conditions such as scoliosis or obesity, as well as occupational situations such as the wearing of bullet-proof vests. This study investigated the hypothesis that tightened football shoulder pads produce decrements in pulmonary function similar to those shown in previous studies involving other external chest-wall restricting devices.”

Conclusion:

“Results are consistent with a restrictive condition and support our hypothesis that tightened shoulder pads reduce pulmonary function. Further studies remain to be performed to determine whether these changes lead to decreased exercise performance and whether equipment modifications can be made to limit alterations in pulmonary function without decreasing the protective value of the pads.”

Therefore it appears that protective equipment increases breathing effort and reduces operational performance. POWERbreathe Inspiratory Muscle Training reverses these impairments.

Read The Effect Of Football Shoulder Pads On Pulmonary Function >

Benefits For Uniformed Services

  • Improved breathing conditions in people with physically demanding occupational situations where breathing demand is raised or where breathing apparatus is used, such as the Armed Forces, Police Force and Fire Service
  • Improved inspiratory muscle strength by 31.2%
  • Improved inspiratory muscle endurance by 27.8%
  • Reduced breathlessness
  • Reduced heart rate
  • Reduced the rate of air use from the breathing cylinder used by firefighters (increasing wear time by around 1.5 min from a 15 min cylinder)
  • Increased time to exhaustion during a standard laboratory treadmill test

Effects of High-Intensity Inspiratory Muscle Training Following a Near-Fatal Gunshot Wound

“Severe injuries sustained during combat may classify individuals as undeployable for active service. It is imperative that every effort is made to optimize physical function following such injuries.”

“In this case, a 38-year-old man sustained a gunshot wound during armed combat. The bullet entered via the left axilla and exited from the right side of the abdomen, resulting in severe thoracic and abdominal injuries. The main goals of therapy were to reduce dyspnea on exertion and to enable return to full work duties. A program of high-intensity, interval-based threshold inspiratory muscle training (IMT) was undertaken.”

Conclusion:

“Given that IMT was introduced 12 months following the injury, at which point progress had reached a plateau with other rehabilitation strategies, it seems reasonable to attribute the increased maximum forced inspiratory flow recorded at rest and change in the locus of symptom limitation during exercise from the dyspnea to leg fatigue to the introduction of IMT. These data should be seen as hypothesis-generating.”

Clinical Implications and Future Research:

“The flow-volume loops recorded during the CPET allowed us to identify inefficiencies in breathing strategy and respiratory mechanics that were responsible for this patient’s intolerable dyspnea during exercise. Notably, the measurement of Pimax was of no diagnostic value and was used only to prescribe the initial load for IMT. These findings suggest that static measures of the pressure-generating capacity of the inspiratory pump muscles convey little information about how they operate under dynamic conditions such as exercise. In this patient, chest fluoroscopy and the CPET with flow-volume loops provided the most useful diagnostic information. A program of high-intensity IMT should be considered for individuals who demonstrate inspiratory flows during exercise that approximate the maximum inspiratory flow recorded at rest. Further study is needed to confirm the role of IMT in people with diaphragm injury.”

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Do Fire-Fighters Develop Specific Ventilatory Responses In Order To Cope With Exercise

“In this study we compared the ventilatory performance whilst wearing self-contained breathing apparatus (SCBA) during exercise, of a group of male fire-fighters with a matched group of male civilians.”

Conclusion:

“Data suggests that the respiratory responses of firefighters while wearing SCBA, which are characterised by increases in breathing frequency but not tidal volume, may help to reduce their breathlessness during exercise while wearing SCBA.”

Read Do fire-fighters develop specific ventilatory responses in order to cope with exercise whilst wearing self-contained breathing apparatus? >

POWERbreathe for Firefighters with Chronic Respiratory Conditions

A study recently published (February 2014) in the International Archives of Occupational and Environmental Health assessed the prevalence of chronic respiratory conditions in (South Australian) metropolitan fire fighters. It also studied associations between occupational exposure, use of respiratory protection and health-related quality of life (HRQoL) in firefighters with and without chronic respiratory conditions.

Study: Chronic respiratory conditions in a cohort of metropolitan fire-fighters: associations with occupational exposure and quality of life.

Methods:

Respiratory symptoms, medical conditions, occupational tasks and exposures and consistency of using respiratory protection were inquired by questionnaire. The Health Survey was used to measure physical and mental health-related quality of life.

Fire-fighters were categorised in subgroups: asthma; COPD/emphysema/chronic bronchitis; no chronic respiratory conditions; and as being ‘not involved’ or ‘involved’ in fire-fighting tasks, the latter further categorised as ‘consistent’ or ‘inconsistent’ use of respiratory protection.

Conclusions:

Ten percent of metropolitan fire-fighters reported underlying chronic respiratory conditions. Presence of such a condition in combination with suboptimal protection from inhaled exposures may lead to poorer physical health-related quality of life.

Read Abstract: Chronic respiratory conditions in a cohort of metropolitan fire-fighters: associations with occupational exposure and quality of life.

How could POWERbreathe help?

A project conducted at the University of Birmingham Sports Medicine and Human Performance Unit into the respiratory performance in firefighters unearthed some not-so-surprising findings:

  • Lung function is impaired whilst wearing SCBA (Self-Contained Breathing Apparatus)
  • Respiratory muscle strength and lung function are impaired further after physical work in SCBA
  • Firefighters adopt a special breathing strategy to minimise the breathlessness induced by working in SCBA

Looking at data from scientific studies, if firefighters performed POWERbreathe Inspiratory Muscle Training for a minimum of 4-weeks, they could:

  • Increase their inspiratory muscle strength
  • Reduce breathlessness
  • Reduce heart rate (1)
  • Reduce the rate of air use from the cylinder (increasing wear time by around 1.5 min from a 15 min cylinder) (1)
  • Increase time to exhaustion (findings from a standard laboratory treadmill test)

(1) Donovan K, McConnell A. Fire-fighters’ Self-contained Breathing Apparatus (SCBA): The Effects of Inspiratory Muscle Training (IMT) during Fire-Fighting Simulations in the Laboratory. In: Hanson, Lovesey, Robertson, editors. Annual Conference of the Ergonomics Society; 1999: Ergonomics Society; 1999. p. 348-52.

Read more about how POWERbreathe could benefit those in the Fire Service.