Inspiratory muscle performance in endurance-trained elderly males during incremental exercise

Mouth occlusion pressure at 100ms (P0.1) as a respiratory biomarker in amyotrophic lateral sclerosis

INTRODUCTION

Airway pressure in the first 100ms of an occluded inspiration (P0.1) evaluates the respiratory center activity, increasing in the presence of respiratory muscle weakness. It is uncertain if its activity can compensate for respiratory muscles weakness in amyotrophic lateral sclerosis (ALS). Methods: Consecutive ALS patients with P0.1 evaluated at first visit were included. Depending on P0.1 percentile, patients were divided in three groups: G1 (<25th percentile); G2 (25th-74th percentiles); G3 (≥75th percentile); two subgroups were further considered: SG0 (<10th percentile); SG1 (>90th percentile). Body mass index (BMI), functional ALS rating scale and its subscores, respiratory function tests, including forced vital capacity, maximal inspiratory (MIP) and expiratory pressures, percentage of P0.1 (%P0.1), blood gas analyses, phrenic nerve motor amplitude (MeanPhrenAmpl) were compared. P0.1/MIP and %P0.1 predictors were explored by linear and multinomial logistic regression analyses. p < 0.05 was considered as significant. Results: From the 497 patients included, 124 were in G1 and G3 each, 249 in G2, 49 in SG0 and SG1 each. G1 included more men, with higher BMI (p < 0.001). G3 had older women, with predominant bulbar phenotype (p < 0.001). Lower respiratory function (p < 0.05) was present in both groups. SG0 (%P0.1 < 51.73%, P0.1/MIP = 1.48 ± 1.02) had more spinal-onset men (p < 0.001) with lower MeanPhrenAmpl (p < 0.004). SG1 (P0.1 > 147.12, P0.1/MIP = 7.92 ± 4.62) predominantly included older patients (p = 0.033), women (p = 0.012), with lower MeanPhrenAmpl (p = 0.039). Discussion: ALS patients with respiratory failure can show high or low P01 values, related to phenotype. Possible central drive reactivity and exhaustion, and the role of respiratory-metabolic-renal buffering system should be further addressed.

Inspiratory muscle training improves performance of a repeated sprints ability test in professional soccer players

BACKGROUND

Inspiratory muscle training (IMT) is an important method of attenuating both respiratory and peripheral effort perceptions, consequently improving neuromuscular performance and resulting in greater improvements in exercise capacity than exercise training alone.

OBJECTIVE

The aim of this study was to investigate the effects of IMT on exercise tolerance, repeated sprint ability (RSA) performance, maximal inspiratory pressure (MIP), and peak inspiratory flow (PIF) in a cohort of professional male soccer players.

METHODS

Twenty-two healthy male professional soccer players (18.3 ± 1.4 years; 174.5 ± 6.1 cm; 70.5 kg ± 4.6 kg; body fat 10.1 ± 4.2%) from a club in the Brazilian first division soccer league participated in this study. IMT consisted of 15 and 30 self-paced inspiratory breaths (each to 50% maximal static inspiratory pressure [P₀]) in the 1-and 2-week intervention period, respectively. IMT was performed prior to soccer training (1 sets.d^-1; 6 d.wk^-1) with repeated sprint ability (RSA) assessed pre- and post- the 2-week period of IMT.

RESULTS

Statistical analyses identified a significant (p < 0.001) decrease in sprint time post-IMT. Additionally, RSA_best, RSA_mean, total sprint time and percentage of RSA performance decrement (RSA _{% dec}) also showed significant decreases (p < 0.0001) post-IMT. Additional measures including MIP and PIF were also significantly elevated (p < 0.0002) following the 2-week period of IMT.

CONCLUSION

In conclusion, our results raise two important issues. Firstly, IMT demonstrated enhanced inspiratory muscle strength in professional soccer players. Secondly, this increase in inspiratory muscle efficiency led to a decrease in sprint time and improved exercise tolerance. We recommend that a standard training protocol be developed and tested in an experimental and control group with a large representative sample.