Association Between Inspiratory Muscle Function and Balance Ability in Older People: A Pooled Data Analysis Before and After Inspiratory Muscle Training.

Inspiratory muscle training (IMT) improved balance ability and respiratory muscle function in healthy older adults. The current study is a retrospective analysis to explore the relationship between inspiratory muscle function, balance ability, and adaptation to IMT. All participants (total = 129; IMT = 60; age range = 65-85 years) performed inspiratory and balance assessments, including the mini-balance evaluation system test, maximal inspiratory pressure, and peak inspiratory flow tests. Baseline inspiratory muscle function was positively related to balance ability (p < .05), and IMT-induced improvements in inspiratory function (23.3% in maximal inspiratory pressure, 8.0% in peak inspiratory flow rate, 14.9% in maximal peak inspiratory power) were related to improvements in balance (10.6% in mini-balance evaluation system test), with the greatest improvements (17.0%) observed in the oldest participants (76-85 years old, p < .05). In conclusion, with or without IMT, positive associations between inspiratory function and balance ability exist, with greater improvements in inspiratory muscle function related to greater improvements in balance ability.

"Why would you want to stand?" an account of the lived experience of employees taking part in a workplace sit-stand desk intervention.

BACKGROUND: Sit-stand desk interventions have the potential to reduce workplace sedentary behaviour and improve employee health. However, the extent of sit-stand desk use varies between employees and in different organisational contexts. Framed by organisational cultural theory and product design theory, this study examined employees' lived experience of taking part in a workplace sit-stand desk intervention, to understand the processes influencing feasibility and acceptability. METHODS: Participant observations and qualitative interviews were conducted with 15 employees from two office-based workplaces in the UK, as part of a process evaluation that ran alongside a pilot RCT of a workplace sit-stand desk intervention. Observational field notes and transcripts were analysed using thematic analysis. RESULTS: Three themes related to the experience of using a sit-stand desk at work were generated: employees' relationship with their sit-stand desk; aspirations and outcomes related to employee health and productivity; and cultural norms and interpersonal relationships. The perceived usability of the desk varied depending on how employees interacted with the desk within their personal and organisational context. Employees reported that the perceived influence of the desk on their productivity levels shaped use of the desk; those who perceived that standing increased energy and alertness tended to stand more often. Sit-stand desks were voiced as being more acceptable than intervention strategies that involve leaving the desk, as productivity was conflated with being at the desk. CONCLUSIONS: The findings indicate a range of organisational, social-cultural and individual-level factors that shape the feasibility and acceptability of sit-stand desk use, and suggest strategies for improving employees' experiences of using a sit-stand desk at work, which might positively influence sedentary behaviour reduction and health. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT02172599, 22nd June 2014 (prospectively registered).

Randomised controlled trial of adjunctive inspiratory muscle training for patients with COPD.

BACKGROUND: This study aimed to investigate whether adjunctive inspiratory muscle training (IMT) can enhance the well-established benefits of pulmonary rehabilitation (PR) in patients with COPD. METHODS: 219 patients with COPD (FEV1: 42%±16% predicted) with inspiratory muscle weakness (PImax: 51±15 cm H2O) were randomised into an intervention group (IMT+PR; n=110) or a control group (Sham-IMT+PR; n=109) in this double-blind, multicentre randomised controlled trial between February 2012 and October 2016 (ClinicalTrials.gov NCT01397396). Improvement in 6 min walking distance (6MWD) was a priori defined as the primary outcome. Prespecified secondary outcomes included respiratory muscle function and endurance cycling time. FINDINGS: No significant differences between the intervention group (n=89) and the control group (n=85) in improvements in 6MWD were observed (0.3 m, 95% CI -13 to 14, p=0.967). Patients who completed assessments in the intervention group achieved larger gains in inspiratory muscle strength (effect size: 1.07, p<0.001) and endurance (effect size: 0.79, p<0.001) than patients in the control group. 75 s additional improvement in endurance cycling time (95% CI 1 to 149, p=0.048) and significant reductions in Borg dyspnoea score at isotime during the cycling test (95% CI -1.5 to -0.01, p=0.049) were observed in the intervention group. INTERPRETATION: Improvements in respiratory muscle function after adjunctive IMT did not translate into additional improvements in 6MWD (primary outcome). Additional gains in endurance time and reductions in symptoms of dyspnoea were observed during an endurance cycling test (secondary outcome) TRIAL REGISTRATION NUMBER: NCT01397396; Results.

"Functional" Inspiratory and Core Muscle Training Enhances Running Performance and Economy.

Tong, TK, McConnell, AK, Lin, H, Nie, J, Zhang, H, and Wang, J. "Functional" inspiratory and core muscle training enhances running performance and economy. J Strength Cond Res 30(10): 2942-2951, 2016-We compared the effects of two 6-week high-intensity interval training interventions. Under the control condition (CON), only interval training was undertaken, whereas under the intervention condition (ICT), interval training sessions were followed immediately by core training, which was combined with simultaneous inspiratory muscle training (IMT)-"functional" IMT. Sixteen recreational runners were allocated to either ICT or CON groups. Before the intervention phase, both groups undertook a 4-week program of "foundation" IMT to control for the known ergogenic effect of IMT (30 inspiratory efforts at 50% maximal static inspiratory pressure [P0] per set, 2 sets per day, 6 days per week). The subsequent 6-week interval running training phase consisted of 3-4 sessions per week. In addition, the ICT group undertook 4 inspiratory-loaded core exercises (10 repetitions per set, 2 sets per day, inspiratory load set at 50% post-IMT P0) immediately after each interval training session. The CON group received neither core training nor functional IMT. After the intervention phase, global inspiratory and core muscle functions increased in both groups (p ≤ 0.05), as evidenced by P0 and a sport-specific endurance plank test (SEPT) performance, respectively. Compared with CON, the ICT group showed larger improvements in SEPT, running economy at the speed of the onset of blood lactate accumulation, and 1-hour running performance (3.04% vs. 1.57%, p ≤ 0.05). The changes in these variables were interindividually correlated (r ≥ 0.57, n = 16, p ≤ 0.05). Such findings suggest that the addition of inspiratory-loaded core conditioning into a high-intensity interval training program augments the influence of the interval program on endurance running performance and that this may be underpinned by an improvement in running economy.

The effect of a sit-stand workstation intervention on daily sitting, standing and physical activity: protocol for a 12 month workplace randomised control trial.

BACKGROUND: A lack of physical activity and excessive sitting can contribute to poor physical health and wellbeing. The high percentage of the UK adult population in employment, and the prolonged sitting associated with desk-based office-work, make these workplaces an appropriate setting for interventions to reduce sedentary behaviour and increase physical activity. This pilot study aims to determine the effect of an office-based sit-stand workstation intervention, compared with usual desk use, on daily sitting, standing and physical activity, and to examine the factors that underlie sitting, standing and physical activity, within and outside, the workplace. METHODS/DESIGN: A randomised control trial (RCT) comparing the effects of a sit-stand workstation only and a multi-component sit-stand workstation intervention, with usual desk-based working practice (no sit-stand workstation) will be conducted with office workers across two organisations, over a 12 month period (N = 30). The multicomponent intervention will comprise organisational, environmental and individual elements. Objective data will be collected at baseline, and after 2-weeks, 3-months, 6-months and 12-months of the intervention. Objective measures of sitting, standing, and physical activity will be made concurrently (ActivPAL3™ and ActiGraph (GT3X+)). Activity diaries, ethnographic participant observation, and interviews with participants and key organisational personnel will be used to elicit understanding of the influence of organisational culture on sitting, standing and physical activity behaviour in the workplace. DISCUSSION: This study will be the first long-term sit-stand workstation intervention study utilising an RCT design, and incorporating a comprehensive process evaluation. The study will generate an understanding of the factors that encourage and restrict successful implementation of sit-stand workstation interventions, and will help inform future occupational wellbeing policy and practice. Other strengths include the objective measurement of physical activity during both work and non-work hours. TRAIL REGISTRATION: Clinicaltrials.gov identifier NCT02172599, 22nd June 2014.

Training the equine respiratory muscles: Inspiratory muscle strength.

BACKGROUND: Little is known about the response of the equine respiratory muscles to training. OBJECTIVES: To measure an index of inspiratory muscle strength (IMSi) before and after a period of conventional exercise training (phase 1) and inspiratory muscle training (IMT), comparing high-load (treatment) and low-load (control) groups (phase 2). STUDY DESIGN: Prospective randomised controlled trial. METHODS: Phase 1: Twenty National Hunt Thoroughbred racehorses performed an inspiratory muscle strength test (IMST) twice on two occasions; when unfit at timepoint A (July), and when race fit at timepoint B (October). Phase 2: Thirty-five Thoroughbred racehorses at race fitness were randomly assigned into a high-load (treatment, n = 20) or low-load (control, n = 15) IMT group. The high-load group followed an IMT protocol that gradually increased the inspiratory pressure applied every 4 days. The low-load group underwent sham IMT with a low training load. The IMT was performed 5 days/week for 10 weeks. The IMST was performed twice on two occasions, timepoint B (October) and timepoint C (January). Conventional exercise training and racing continued during the study period. The peak IMSi values obtained from the different groups at timepoints A, B and C were compared using a Wilcoxon Signed Rank Test. RESULTS: Phase 1: There was a significant increase in IMSi from timepoint A: 22.5 cmH2 O (21-25) to timepoint B: 26 cmH2 O (24-30) (p = 0.015). Phase 2: From timepoint B to C there was a significant increase in IMSi for the high-load group 34 cmH2 O (28-36) (p = 0.001) but not the low-load group 26 cmH2 O (24-30) (p = 0.929). The peak IMSi at timepoint C was significantly higher for the high-load than low-load group (p = 0.019). MAIN LIMITATIONS: Single centre study with only National Hunt horses undergoing race-training included. CONCLUSIONS: In horses undergoing race training there is a significant increase in IMSi in response to conventional exercise training and high-load IMT.

Training the equine respiratory muscles: Ultrasonographic measurement of muscle size.

BACKGROUND: Limited information exists regarding changes in the size of respiratory and locomotor muscles in response to exercise training in the Thoroughbred racehorse. OBJECTIVES: To describe and compare the responses of the respiratory and locomotor muscles to conventional exercise training and inspiratory muscle training (IMT). STUDY DESIGN: Prospective randomised controlled trial. METHODS: Thoroughbred racehorses, in training for competition in National Hunt races, were recruited from two training establishments. Ultrasonographic images were obtained for selected muscles of the upper airway, diaphragm, accessory respiratory, and locomotor systems and their sizes measured. Examinations were performed at three timepoints: (A) when unfit, (B) following 12 weeks of conventional exercise training and (C) following 10-12 weeks continued training at race fitness. In addition, horses at yard 1 performed IMT, between timepoint B and C, and were randomly assigned into high-load (treatment) or low-load (control) group. Repeated measures models were constructed to compare the change in muscle measurements over time, and to investigate the effects of yard, previous airway surgery and IMT on the change in ultrasonographic size measurements obtained. RESULTS: Upper airway muscle size increased in response to conventional race training between timepoints A-C, and B-C. Diaphragm size increased in response to conventional exercise training between timepoints A and B. The diaphragm size of horses that undertook high-load IMT was either maintained or increased, whereas diaphragm size decreased in horses that undertook low-load IMT or no IMT between timepoints B and C. A significant interaction between gluteal muscle size and airway surgery status was observed, with greater gluteal muscle thicknesses measured in horses that had not previously undergone airway surgery (left gluteal 3.9%, p < 0.001; right 4.5%, p = 0.04). MAIN LIMITATIONS: Low number of horses underwent IMT. CONCLUSIONS: Respiratory and locomotor muscles increase in size in response to conventional exercise training, with a further change in diaphragm size in response to inspiratory muscle training.

The influence of rowing-related postures upon respiratory muscle pressure and flow generating capacity.

During the rowing stroke, the respiratory muscles are responsible for postural control, trunk stabilisation, generation/transmission of propulsive forces and ventilation (Bierstacker et al. in Int J Sports Med 7:73-79, 1986; Mahler et al. in Med Sci Sports Exerc 23:186-193, 1991). The challenge of these potentially competing requirements is exacerbated in certain parts of the rowing stroke due to flexed (stroke 'catch') and extended postures (stroke 'finish'). The purpose of this study was to assess the influence of the postural role of the trunk muscles upon pressure and flow generating capacity, by measuring maximal respiratory pressures, flows, and volumes in various seated postures relevant to rowing. Eleven male and five female participants took part in the study. Participants performed two separate testing sessions using two different testing protocols. Participants performed either maximal inspiratory or expiratory mouth pressure manoeuvres (Protocol 1), or maximal flow volume loops (MFVLs) (Protocol 2), whilst maintaining a variety of specified supported or unsupported static rowing-related postures. Starting lung volume was controlled by initiating the test breath in the upright position. Respiratory mouth pressures tended to be lower with recumbency, with a significant decrease in P (Emax) in unsupported recumbent postures (3-9 % compared to upright seated; P = 0.036). There was a significant decrease in function during dynamic manoeuvres, including PIF (5-9 %), FVC (4-7 %) and FEV(1) (4-6 %), in unsupported recumbent postures (p < 0.0125; Bonferroni corrected). Thus, respiratory pressure and flow generating capacity tended to decrease with recumbency; since lung volumes were standardised, this may have been, at least in part, influenced by the postural co-contraction of the trunk muscles.

A preliminary biomechanical study of cyclic preconditioning effects on canine cadaveric whole femurs.

Biomechanical preconditioning of biological specimens by cyclic loading is routinely done presumably to stabilize properties prior to the main phase of a study. However, no prior studies have actually measured these effects for whole bone of any kind. The aim of this study, therefore, was to quantify these effects for whole bones. Fourteen matched pairs of fresh-frozen intact cadaveric canine femurs were sinusoidally loaded in 4-point bending from 50 N to 300 N at 1 Hz for 25 cycles. All femurs were tested in both anteroposterior (AP) and mediolateral (ML) bending planes. Bending stiffness (i.e., slope of the force-vs-displacement curve) and linearity R(2) (i.e., coefficient of determination) of each loading cycle were measured and compared statistically to determine the effect of limb side, cycle number, and bending plane. Stiffnesses rose from 809.7 to 867.7 N/mm (AP, left), 847.3 to 915.6 N/mm (AP, right), 829.2 to 892.5 N/mm (AP, combined), 538.7 to 580.4 N/mm (ML, left), 568.9 to 613.8 N/mm (ML, right), and 553.8 to 597.1 N/mm (ML, combined). Linearity R(2) rose from 0.96 to 0.99 (AP, left), 0.97 to 0.99 (AP, right), 0.96 to 0.99 (AP, combined), 0.95 to 0.98 (ML, left), 0.94 to 0.98 (ML, right), and 0.95 to 0.98 (ML, combined). Stiffness and linearity R(2) versus cycle number were well-described by exponential curves whose values leveled off, respectively, starting at 12 and 5 cycles. For stiffness, there were no statistical differences for left versus right femurs (p = 0.166), but there were effects due to cycle number (p < 0.0001) and AP versus ML bending plane (p < 0.0001). Similarly, for linearity, no statistical differences were noted due to limb side (p = 0.533), but there were effects due to cycle number (p < 0.0001) and AP versus ML bending plane (p = 0.006). A minimum of 12 preconditioning cycles was needed to fully stabilize both the stiffness and linearity of the canine femurs. This is the first study to measure the effects of mechanical preconditioning on whole bones, having some practical implications on research practices.

Respiratory-related limitations in physically demanding occupations.

Respiratory muscle work limits high-intensity exercise tolerance in healthy human beings. Emerging evidence suggests similar limitations exist during submaximal work in some physically demanding occupations. In an occupational setting, heavy loads are routinely carried upon the trunk in the form of body armor, 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. More specifically, thoracic load carriage induces a restrictive ventilatory limitation which increases the elastic work of breathing, rendering the respiratory muscles vulnerable to fatigue and inducing a concomitant reduction in exercise tolerance. Similarly, breathing apparatus worn by occupational personnel, including fire fighters and military and commercial divers, increases the inspiratory elastic and expiratory resistive work of breathing, precipitating significant inspiratory and expiratory muscle fatigue and a reduction in exercise tolerance. 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.

Biomechanical measurements of torsion-tension coupling in human cadaveric femurs.

The mechanical behavior of human femurs has been described in the literature with regard to torsion and tension but only as independent measurements. However, in this study, human femurs were subjected to torsion to determine if a simultaneous axial tensile load was generated. Fresh frozen human femurs (n=25) were harvested and stripped of soft tissue. Each femur was mounted rigidly in a specially designed test jig and remained at a fixed axial length during all experiments. Femurs were subjected to external and internal rotation applied at a constant angulation rate of 0.1 deg/s to a maximum torque of 12 N m. Applied torque and generated axial tension were monitored simultaneously. Outcome measurements were extracted from torsion-versus-tension graphs. There was a strong relationship between applied torsion and the resulting tension for external rotation tests (torsion/tension ratio=551.7±283.8 mm, R(2)=0.83±0.20, n=25), internal rotation tests (torsion/tension ratio=495.3±233.1 mm, R(2)=0.87±0.17, n=24), left femurs (torsion/tension ratio=542.2±262.4 mm, R(2)=0.88±0.13, n=24), and right femurs (torsion/tension ratio=506.7±260.0 mm, R(2)=0.82±0.22, n=25). No statistically significant differences were found for external versus internal rotation groups or for left versus right femurs when comparing torsion/tension ratios (p=0.85) or R(2) values (p=0.54). A strongly coupled linear relationship between torsion and tension for human femurs was exhibited. This suggests an interplay between these two factors during activities of daily living and injury processes.

Diagnosis of exercise-induced bronchoconstriction: eucapnic voluntary hyperpnoea challenges identify previously undiagnosed elite athletes with exercise-induced bronchoconstriction.

BACKGROUND: There is increasing evidence to suggest many elite athletes fail to recognise and report symptoms of exercise-induced bronchoconstriction (EIB), supporting the contention that athletes should be screened routinely for EIB. PURPOSE: To screen elite British athletes for EIB using eucapnic voluntary hyperpnoea (EVH). METHODS: 228 elite athletes provided written informed consent and completed an EVH challenge with maximal flow volume loops measured at baseline and 3, 5, 10 and 15 min following EVH. A fall of 10% in forced expiratory volume in 1 s (FEV(1)) from baseline was deemed positive. Two-way analysis of variance was conducted to compare FEV(1) at baseline and maximal change following EVH between EVH-positive and EVH-negative athletes who did and did not report a previous diagnosis of EIB. Significance was assumed if p ≤0.05. RESULTS: Following the EVH challenge 78 athletes (34%) demonstrated EVH positive. 57 out of the 78 (73%) athletes who demonstrated EVH positive did not have a previous diagnosis of EIB. 30 athletes reported a previous diagnosis of asthma, nine (30%) of whom demonstrated EVH negative. There was no significant difference between the magnitude of the fall in FEV(1) between athletes who reported a previous diagnosis of EIB and demonstrated EVH positive, and those with no previous diagnosis of EIB who demonstrated EVH positive (mean±SD; -21.6 ± 16.1% vs -17.1 ± 9.7%; p=0.07). CONCLUSION: The high proportion of previously undiagnosed athletes who demonstrated EVH positive suggests that elite athletes should be screened routinely for EIB using a suitable bronchoprovocation challenge.

Inspiratory muscle training improves 100 and 200 m swimming performance.

Inspiratory muscle training (IMT) has been shown to improve time trial performance in competitive athletes across a range of sports. Surprisingly, however, the effect of specific IMT on surface swimming performance remains un-investigated. Similarly, it is not known whether any ergogenic influence of IMT upon swimming performance is confined to specific race distances. To determine the influence of IMT upon swimming performance over 3 competitive distances, 16 competitive club-level swimmers were assigned at random to either an experimental (pressure threshold IMT) or sham IMT placebo control group. Participants performed a series of physiological and performance tests, before and following 6 weeks of IMT, including (1) an incremental swim test to the limit of tolerance to determine lactate, heart rate and perceived exertion responses; (2) standard measures of lung function (forced vital capacity, forced expiratory volume in 1 s, peak expiratory flow) and maximal inspiratory pressure (MIP); and (3) 100, 200 and 400 m swim time trials. Training utilised a hand-held pressure threshold device and consisted of 30 repetitions, twice per day. Relative to control, the IMT group showed the following percentage changes in swim times: 100 m, -1.70% (90% confidence limits, +/-1.4%), 200 m, -1.5% (+/-1.0), and 400 m, 0.6% (+/-1.2). Large effects were observed for MIP and rates of perceived exertion. In conclusion, 6 weeks of IMT has a small positive effect on swimming performance in club-level trained swimmers in events shorter than 400 m.

Inspiratory muscle training and testing: Rationale, development and feasibility.

BACKGROUND: Inspiratory muscle training applies a training stimulus directly to the inspiratory muscles and is distinct from whole-body training. The potential benefits of inspiratory muscle training have yet to be explored in horses. OBJECTIVES: The objectives were as follows: (a) to develop an equine-specific method of testing and training inspiratory muscles; (b) to assess tolerance and feasibility in a pilot study in a commercial Thoroughbred training establishment. STUDY DESIGN: Field study. METHODS: A mask was used to interface commercial human inspiratory muscle training equipment. Ten horses undertook inspiratory muscle training once daily while stood in the stable approximately 5 days/wk over a 9-week period. Inspiratory muscle strength testing employed a continuous incremental inspiratory loading protocol alternating two loaded and two minimally loaded breaths until failure to tolerate the load occurred or the maximum 60 breaths were completed. The inspiratory muscle strength testing was undertaken twice; firstly, in 10 horses with minimal acclimatisation and secondly, in eight horses experienced with the inspiratory muscle training programme. RESULTS: The 10 horses undertook inspiratory muscle training for a median of 42 days, reaching a median peak training load of 32.5 cm H2 O. One horse did not tolerate the mask with repeated snorting and was replaced. All horses completed the inspiratory muscle strength testing. The median peak value in inspiratory muscle strength testing protocol 1 was 27 cm H2 O and in inspiratory muscle strength testing protocol 2 was 41 cm H2 O. Two of 10 horses reached the maximum possible value in inspiratory muscle strength testing protocol 1; therefore, the test was adapted to permit a higher maximum value, despite this 3/8 horses reached the maximum possible value in inspiratory muscle strength testing protocol 2. MAIN LIMITATIONS: A small number of horses were assessed. The inspiratory muscle strength testing protocol was refined during the study and requires additional refinement. CONCLUSION: Inspiratory muscle testing and training were feasible and tolerated in horses. Further research is required to understand whether the inspiratory muscle strength testing values obtained correlate with other physiological/performance outcomes. The potential benefits and/or adverse effects of inspiratory muscle training warrant further investigation.

Comparison of balance changes after inspiratory muscle or Otago exercise training.

The inspiratory muscles contribute to balance via diaphragmatic contraction and by increasing intra-abdominal pressure. We have shown inspiratory muscle training (IMT) improves dynamic balance significantly with healthy community-dwellers. However, it is not known how the magnitude of balance improvements following IMT compares to that of an established balance program. This study compared the effects of 8-week of IMT for community-dwellers, to 8-week of the Otago exercise program (OEP) for care-residents, on balance and physical performance outcomes. Nineteen healthy community-dwellers (74 ± 4 years) were assigned to self-administered IMT. Eighteen, healthy care-residents (82 ± 4 years) were assigned to instructor-led OEP. The IMT involved 30 breaths twice-daily at ~50% of maximal inspiratory pressure (MIP). The OEP group undertook resistance and mobility exercises for ~60 minutes, twice-weekly. Balance and physical performance were assessed using the mini Balance Evaluation System Test (mini-BEST) and time up and go (TUG). After 8-week, both groups improved balance ability significantly (mini-BEST: IMT by 24 ± 34%; OEP by 34 ± 28%), with no between-group difference. Dynamic balance sub-tasks improved significantly more for the IMT group (P < 0.01), than the OEP group and vice versa for static balance sub-tasks (P = 0.01). The IMT group also improved MIP (by 66 ± 97%), peak inspiratory power (by 31 ± 12%) and TUG (by -11 ± 27%); whereas the OEP did not. IMT and OEP improved balance ability similarly, with IMT eliciting greater improvement in dynamic balance, whilst OEP improved static balance more than IMT. Unlike IMT, the OEP did not provide additional benefits in inspiratory muscle function and TUG performance. Our findings suggest that IMT offers a novel method of improving dynamic balance in older adults, which may be more relevant to function than static balance and potentially a useful adjunct to the OEP in frailty prevention.

Influence of different breathing frequencies on the severity of inspiratory muscle fatigue induced by high-intensity front crawl swimming.

The aim of the present study was to assess the influence of 2 different breathing frequencies on the magnitude of inspiratory muscle fatigue after high-intensity front crawl swimming. The influence of different breathing frequencies on postexercise blood lactate ([La]) and heart rate (HR) was also examined. Ten collegiate swimmers performed 2 x 200-m front crawl swims at 90% of race pace with the following breathing frequencies: 1) 1 breath every second stroke (B2), and 2) 1 breath every fourth stroke (B4). Maximal inspiratory pressure (PImax) was measured at the mouth from residual volume before (baseline) and after swimming, in a standing position. The HR and [La] were assessed at rest and immediately at the cessation of swimming. The PImax decreased by 21% after B4 and by 11% after B2 compared with baseline (p < 0.05). The [La] was lower by 15% after B4 than after B2 (p < 0.05). The HR was not significantly different between B2 and B4. These data suggest that there is significant global inspiratory muscle fatigue after high-intensity swimming. Inspiratory muscle fatigue is, however, greater when breathing frequency is reduced during high-intensity front crawl swimming. Respiratory muscle training should be used to improve respiratory muscle strength and endurance in swimmers.

The effects of 8 weeks of inspiratory muscle training on the balance of healthy older adults: a randomized, double-blind, placebo-controlled study.

To examine the effects of 8-week unsupervised, home-based inspiratory muscle training (IMT) on the balance and physical performance of healthy older adults. Fifty-nine participants (74 ± 6 years) were assigned randomly in a double-blinded fashion to either IMT or sham-IMT, using a pressure threshold loading device. The IMT group performed 30-breath twice daily at ~50% of maximal inspiratory pressure (MIP). The sham-IMT group performed 60-breaths once daily at ~15% MIP; training was home-based and unsupervised, with adherence self-reported through training diaries. Respiratory outcomes were assessed pre- and postintervention, including forced vital capacity, forced expiratory volume, peak inspiratory flow rate (PIFR), MIP, and inspiratory peak power. Balance and physical performance outcomes were measured using the shortened version of the Balance Evaluation System test (mini-BEST), Biodex® postural stability test, timed up and go, five sit-to-stand, isometric "sit-up" and Biering-Sørensen tests. Between-group effects were examined using two-way repeated measures ANOVA, with Bonferroni correction. After 8-week, the IMT group demonstrated greater improvements (P ≤ 0.05) in: PIFR (IMT = 0.9 ± 0.3 L sec-1 ; sham-IMT = 0.3 L sec-1 ); mini-BEST (IMT = 3.7 ± 1.3; sham-IMT = 0.5 ± 0.9) and Biering-Sørensen (IMT = 62.9 ± 6.4 sec; sham-IMT = 24.3 ± 1.4 sec) tests. The authors concluded that twice daily unsupervised, home-based IMT is feasible and enhances inspiratory muscle function and balance for community-dwelling older adults.

The Relationship between Military Combat and Cardiovascular Risk: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVES: Cardiovascular disease (CVD) is a leading cause of death among military veterans with several reports suggesting a link between combat and related traumatic injury (TI) to an increased CVD risk. The aim of this paper is to conduct a widespread systematic review and meta-analysis of the relationship between military combat ± TI to CVD and its associated risk factors. METHODS: PubMed, EmbaseProQuest, Cinahl databases and Cochrane Reviews were examined for all published observational studies (any language) reporting on CVD risk and outcomes, following military combat exposure ± TI versus a comparative nonexposed control population. Two investigators independently extracted data. Data quality was rated and rated using the 20-item AXIS Critical Appraisal Tool. The risk of bias (ROB using the ROBANS 6 item tool) and strength of evidence (SOE) were also critically appraised. RESULTS: From 4499 citations, 26 studies (14 cross sectional and 12 cohort; 78-100% male) met the inclusion criteria. The follow up period ranged from 1 to 43.6 years with a sample size ranging from 19 to 621901 participants in the combat group. Combat-related TI was associated with a significantly increased risk for CVD (RR 1.80: 95% CI 1.24-2.62; I 2 = 59%, p = 0.002) and coronary heart disease (CHD)-related death (risk ratio 1.57: 95% CI 1.35-1.83; I 2 = 0%, p = 0.77: p < 0.0001), although the SOE was low. Military combat (without TI) was linked to a marginal, yet significantly lower pooled risk (low SOE) of cardiovascular death in the active combat versus control population (RR 0.90: CI 0.83-0.98; I 2 = 47%, p = 0.02). There was insufficient evidence linking combat ± TI to any other cardiovascular outcomes or risk factors. CONCLUSION: There is low SOE to support a link between combat-related TI and both cardiovascular and CHD-related mortality. There is insufficient evidence to support a positive association between military combat ± any other adverse cardiovascular outcomes or risk factors. Data from well conducted prospective cohort studies following combat are needed.