ORIGINAL ARTICLE |
https://doi.org/10.5005/jp-journals-11010-1116 |
Utilizing Muscle Energy Techniques for Biomechanical Changes in Chronic Obstructive Pulmonary Disease: Variations in Outcomes Based on Global Initiative for Chronic Obstructive Lung Disease Classification
1–3Department of Physiotherapy, Faculty of Health Sciences, University of Malta, Msida, Malta
Corresponding Author: Anabel Sciriha, Department of Physiotherapy, Faculty of Health Sciences, University of Malta, Msida, Malta, Phone: +35623401573, e-mail: anabel.sciriha@um.edu.mt
Received: 12 January 2024; Accepted: 17 May 2024; Published on: 18 June 2024
ABSTRACT
Background: Muscle energy techniques (METs) are manipulative interventions under current investigation for their impact not only within the musculoskeletal domain, but also in chronic obstructive pulmonary disease (COPD) patients. Previous research reported beneficial effects from a 4-week MET program on pulmonary function, functional capacity, and daily activities. Patients diagnosed with COPD are categorized using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy, to guide tailored treatment regimens for different COPD phenotypes. Given positive outcomes from the MET program across all COPD classifications, investigating outcomes with the different traditional GOLD stages seemed warranted.
Materials and methods: A parallel-group, randomized controlled trial was adopted. A total of 108 participants with COPD were recruited and randomly assigned to the intervention or control group. All patients were classified by the GOLD classification. The intervention group received MET interventions, three-times weekly for 4 consecutive weeks, while the control group continued with their standard medical treatment. The study is clinically registered (clinicaltrials.gov identifier: NCT04773860).
Results: All 108 patients completed the program, showing significant improvements across all three GOLD classifications. A significant difference in forced expiratory volume in 1 second (FEV1) was reported across the three GOLD classifications at both time points (p < 0.001). The changes observed in forced vital capacity (FVC) measures displayed significant differences at week 0 when comparing all three groups (p = 0.039). No statistically significant differences were observed in the other outcome measures.
Conclusion: A 4-week MET program resulted in more significant improvements in lung function measures among more severe COPD patients, whereas no substantial improvements were observed in chest measurements, activities of daily living (ADLs), or exercise tolerance tests when examining the different GOLD stage groups.
Clinical significance: This study shows benefits of a 4-week MET intervention period on patients suffering from COPD, which led to statistically significant improvements resulted within the pulmonary function measures, chest expansion and ADL performance, and improvement in walking distance. All these outcome measurements provide evidence that this technique can be an effective treatment which can be used as an adjunct with other nonpharmacological physiotherapeutic treatments offered to these patients. Analysis per GOLD classification did not result in any differences between the groups based on COPD severity.
How to cite this article: Agius TP, Sevasta K, Sciriha A. Utilizing Muscle Energy Techniques for Biomechanical Changes in Chronic Obstructive Pulmonary Disease: Variations in Outcomes Based on Global Initiative for Chronic Obstructive Lung Disease Classification. Indian J Respir Care 2024;13(2):107–112.
Source of support: Nil
Conflict of interest: None
Keywords: Activities of daily living, Chronic obstructive pulmonary disease, Global Initiative for Chronic Obstructive Lung Disease Classification, Muscle energy techniques
INTRODUCTION
Muscle energy techniques (METs) are manipulative interventions currently under investigation for their impact not only within the musculoskeletal domain, but also in the changes observed in patients diagnosed with chronic obstructive pulmonary disease (COPD).1,2 These techniques are considered safer compared to high velocity manipulations due to their absence of rapid thrust, which could lead to adverse effects, including potential neurovascular complications.3,4 These manual techniques have been observed to target the resultant changes to the musculoskeletal system.3,4 Such changes take place following flattening and shortening of the diaphragm.3,4 As a result of these chronic adaptations, respiratory muscles work at their maximum capacity to meet the demands required during ventilation which therefore result in an increase in the work of breathing.3,4 As a compensatory mechanism for such changes, the accessory muscles of respiration are recruited.1,2 These muscles shorten so as to adapt to this increase in workload, therefore become overactive.1,2 Studies1,2 show that following MET interventions, muscle lengthening takes place resulting in an increase in range of motion, resulting in less thoracic wall stiffness.3 Improvements in rate of respiration, forced expiratory volume in 1 second (FEV1), and improvements in oxygen saturation are also reported.2
Previous research by the authors of this paper reported beneficial effects as a result of 4-week MET program on pulmonary function, functional capacity, and activities of daily living (ADL).1 Post-intervention results show significant improvements in pulmonary function (p < 0.001), chest measurements (p < 0.001), and ADLs (p < 0.001), with clinically significant improvements in the 6-minute walking distance (6MWD) (p = 0.08).
Patients diagnosed with COPD are categorized using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy. This strategy considers airflow limitation (FEV1), symptoms [using modified Medical Research Council (mMRC) dyspnea scale or the COPD Assessment Test (CAT) score], and exacerbation history, to guide tailored treatment regimens for different COPD phenotypes.5 Given positive outcomes from the MET program across all COPD classifications, investigating outcomes with the different traditional GOLD stages seemed warranted.
MATERIALS AND METHODS
Sample Size
A total of 108 participants were recruited, if they met the inclusion criteria and provided written consent for participation. The inclusion criteria consisted of diagnosis of COPD by a medical consultant, no exacerbations within the last three months, and an age range of 40–79 years. Any participant with rheumatoid arthritis, musculoskeletal or neuromuscular pathologies, or cognitive disabilities were excluded. The intermediary randomly assigned participants to two groups: control or intervention using a random computer generator. Recruitment period took place between May 2021 and February 2022 (Fig. 1).
Fig. 1: Consolidated Standards of Reporting Trials flow diagram
Outcome Measures
Four measures were assessed.
Spirometry
Spirometry tests were carried out using the Spirometry PC software V2.2.4994.11.706 of Carefusion, by Micro Medical Limited. Participants were asked to expire maximally for 6 seconds with FEV1 recorded during the 1st second of maximal expiration, while forced vital capacity (FVC) was measured throughout the test.6
6-minute Walk Distance
The 6-minute walk test (6MWT) was carried out in a 30 m corridor, with participants requested to walk for as much distance as possible in this time frame.7 Standardized verbal prompts were given to motivate participants during the test. Oxygen saturation and the Borg Dyspnea Score were assessed every minute.8 The 6MWT is a reliable, objective, and inexpensive outcome measure used to assess submaximal exercise capacity and functional activity.7
Chest Measurements
A tape measure was used to assess chest measurements. This tool is valid, inexpensive, objective, and reproducible,9 with measurements taken at two points being 4th and 10th vertebral level.
Manchester Respiratory Activities of Daily Living questionnaire
The Manchester Respiratory Activities of Daily Living (MR-ADL), a self-completed scale, assesses functional ability through four different domains: the kitchen, mobility, home duties, and leisure activities.10 Since this tool provides personal information, it aids in designing treatments aimed at maintaining independent living.10 This tool is repeatable and reliable for patients diagnosed with COPD.10
Intervention
The experimental group carried out a one-to-one, 30-minute MET session three times weekly for 4 weeks. METs were applied to the accessory muscles of respiration (upper fibers of trapezius, the three parts of the scalene muscle, sternocleidomastoid, the pectoralis minor, latissimus dorsi, and serratus anterior).11 The Chaitow protocol was followed which states that each muscle is to be individually treated by performing a gentle 7-second isometric contraction, followed by 3 seconds of relaxation. A new barrier for every muscle was approached by means of a passive stretch for 30 seconds. Each technique was applied twice and bilaterally.
The control group continued with their usual medical treatment and were offered the option of undergoing the intervention on completion of the study.
Ethical Considerations
Ethical approval was sought from the University Research Ethics Committee (UREC Form V_15062020 6559) and registered in clinicaltrials.gov identifier: NCT04773860.
Data Analysis
The Statistical Package of Social Science software, version 28 was used. Since data was normally distributed, one-way analysis of variance (ANOVA) test was computed to compare the three GOLD standards, and the independent samples t-test to compare the active and control group.
RESULTS
All 108 patients completed the program, with significant improvements across all three GOLD classifications being reported. All data is reported in Table 1.
| Outcome measure | Number of participants | GOLD classification | Average mean week 0 (SD) | Average mean week 4 (SD) | Average mean week 8 (SD) | |
|---|---|---|---|---|---|---|
| FEV1 | Active group | 14 | GOLD 2 | 77.36 (1.50) | 88.36 (1.82) | 80.36 (3.10) |
| 26 | GOLD 3 | 47.12 (2.25) | 54.04 (3.19) | 52.50 (3.46) | ||
| 13 | GOLD 4 | 26.92 (2.22) | 33.08 (3.64) | 30.92 (3.04) | ||
| p-value | <0.001 | <0.001 | <0.001 | |||
| Control group | 14 | GOLD 2 | 76.64 (1.99) | 76.14 (1.56) | 75.86 (1.35) | |
| 33 | GOLD 3 | 46.55 (2.75) | 46.33 (3.02) | 46.36 (2.63) | ||
| 7 | GOLD 4 | 25 (2.71) | 26.43 (1.72) | 26.29 (2.14) | ||
| p-value | <0.001 | <0.001 | <0.001 | |||
| FVC | Active group | 14 | GOLD 2 | 62.93 (12.98) | 72.36 (12.61) | 68.07 (12.84) |
| 26 | GOLD 3 | 50.81 (13.66) | 61.27 (13.46) | 57.12 (13.55) | ||
| 13 | GOLD 4 | 53.85 (15.51) | 62.85 (14.49) | 59.23 (14.20) | ||
| p-value | 0.039 | 0.049 | 0.056 | |||
| Control group | 14 | GOLD 2 | 57.79 (6.41) | 56.50 (6.89) | 56.93 (6.91) | |
| 33 | GOLD 3 | 54.33 (6.24) | 53.58 (6.44) | 54.18 (6.36) | ||
| 7 | GOLD 4 | 54.71 (6.37) | 54.43 (6.55) | 55 (6.73) | ||
| p-value | 0.231 | 0.385 | 0.427 | |||
| FEV1/FVC | Active group | 14 | GOLD 1 | 64.86 (17.62) | 72.43 (18.21) | 69 (17.32) |
| 26 | GOLD 2 | 66.46 (17.52) | 75.46 (17.11) | 72.27 (17.34) | ||
| 13 | GOLD 3 | 65.62 (18.14) | 75.15 (16.72) | 71.69 (16.92) | ||
| p-value | 0.962 | 0.862 | 0.845 | |||
| Control group | 14 | GOLD 2 | 62.93 (2.67) | 62.57 (3.65) | 61.36 (3.99) | |
| 33 | GOLD 3 | 62.76 (4.26) | 61.67 (4.27) | 60.94 (3.87) | ||
| 7 | GOLD 4 | 65.14 (2.55) | 64.43 (2.70) | 64.14 (1.86) | ||
| p-value | 0.349 | 0.241 | 0.128 | |||
| 6MWD | Active group | 14 | GOLD 2 | 330.86 (109.42) | 359.71 (114.58) | 345.36 (112.45) |
| 26 | GOLD 3 | 356.33 (92.63) | 384.46 (87.50) | 374.96 (94.51) | ||
| 13 | GOLD 4 | 323 (106.71) | 344.92 (101.89) | 340 (100.64) | ||
| p-value | 0.564 | 0.470 | 0.510 | |||
| Control group | 14 | GOLD 2 | 320.50 (97.27) | 311.07 (90.47) | 316.43 (93.16) | |
| 33 | GOLD 3 | 339.88 (101.97) | 342.27 (101.15) | 341.06 (105.07) | ||
| 7 | GOLD 4 | 333 (133.39) | 325 (131.56) | 327.14 (128.97) | ||
| p-value | 0.846 | 0.626 | 0.756 | |||
| Chest expansion T4 level—inspiration | Active group | 14 | GOLD 2 | 92.68 (12.56) | 97.29 (13.81) | 95.69 (13.85) |
| 26 | GOLD 3 | 93.46 (7.84) | 97.69 (9.30) | 95.40 (8.12) | ||
| 13 | GOLD 4 | 90.80 (7.91) | 95.57 (10.49) | 93.15 (9.02) | ||
| p-value | 0.704 | 0.835 | 0.765 | |||
| Control group | 14 | GOLD 2 | 92.19 (9.30) | 92.26 (9.26) | 92.26 (0.26) | |
| 33 | GOLD 3 | 91.28 (7.02) | 91.39 (7.34) | 91.42 (7.41) | ||
| 7 | GOLD 4 | 93.70 (7.23) | 93.71 (7.33) | 93.74 (7.35) | ||
| p-value | 0.74 | 0.77 | 0.769 | |||
| Chest expansion T4 level—expiration | Active group | 14 | GOLD 2 | 91.36 (12.95) | 84.87 (11.47) | 86.51 (11.48) |
| 26 | GOLD 3 | 91.99 (7.83) | 85.56 (8.15) | 88.12 (7.94) | ||
| 13 | GOLD 4 | 89.22 (7.73) | 83.30 (5.87) | 84.88 (6.02) | ||
| p-value | 0.685 | 0.536 | 0.538 | |||
| Control group | 14 | GOLD 2 | 90.66 (9.42) | 90.79 (9.35) | 90.83 (9.39) | |
| 33 | GOLD 3 | 89.92 (7.18) | 89.85 (7.38) | 89.85 (7.51) | ||
| 7 | GOLD 4 | 92.09 (7.16) | 91.97 (7.19) | 91.91 (7.25) | ||
| p-value | 0.792 | 0.792 | 0.801 | |||
| Chest expansion T10 level—inspiration | Active group | 14 | GOLD 2 | 91.42 (16.42) | 94.81 (15.66) | 93.31 (15.96) |
| 26 | GOLD 3 | 92.96 (11.54) | 97.42 (11.62) | 94.77 (11.28) | ||
| 13 | GOLD 4 | 94.22 (12.46) | 99.33 (11.14) | 97.74 (11.23) | ||
| p-value | 0.859 | 0.649 | 0.652 | |||
| Control group | 14 | GOLD 2 | 89 (10.95) | 89.16 (10.91) | 89.13 (10.99) | |
| 33 | GOLD 3 | 90.99 (11.55) | 90.94 (11.56) | 90.81 (11.71) | ||
| 7 | GOLD 4 | 96.69 (13.29) | 96.77 (13.38) | 96.83 (13.38) | ||
| p-value | 0.362 | 0.365 | 0.361 | |||
| Chest expansion T10—expiration | Active group | 14 | GOLD 2 | 92.72 (16.50) | 87.87 (16.05) | 89.41 (15.70) |
| 16 | GOLD 3 | 92.10 (11.22) | 87.01 (10.76) | 88.55 (10.68) | ||
| 13 | GOLD 4 | 94 (12.37) | 88.85 (12.16) | 90.19 (12.03) | ||
| p-value | 0.912 | 0.911 | 0.925 | |||
| Control group | 14 | GOLD 2 | 88.86 (9.84) | 89.01 (9.93) | 89.08 (9.89) | |
| 33 | GOLD 3 | 90.62 (11.65) | 90.69 (11.63) | 90.79 (11.73) | ||
| 7 | GOLD 4 | 95.06 (13.11) | 95.07 (13.12) | 95.06 (13.12) | ||
| p-value | 0.504 | 0.520 | 0.532 | |||
| MR-ADL | Active group | 14 | GOLD 2 | 17.32 (1.76) | 18.11 (1.29) | 17.95 (1.28) |
| 16 | GOLD 3 | 17.79 (1.24) | 18.37 (0.99) | 18.10 (1.12) | ||
| 13 | GOLD 4 | 17.35 (1.34) | 18.15 (1.23) | 17.98 (1.32) | ||
| p-value | 0.507 | 0.748 | 0.921 | |||
| Control group | 14 | GOLD 2 | 18.13 (1.12) | 18 (1.00) | 17.88 (1.16) | |
| 33 | GOLD 3 | 17.49 (1.11) | 17.44 (1.11) | 17.45 (1.11) | ||
| 7 | GOLD 4 | 17.36 (0.72) | 17.54 (0.80) | 17.57 (0.66) | ||
| p-value | 0.146 | 0.252 |
Changes which were statistically significant are marked in bold; 6MWD, 6-minute walking distance; FEV1, forced expiratory volume in 1 second; FEV1/FVC, ratio for forced expiratory volume to forced vital capacity; FVC, forced vital capacity; MR-ADL, Manchester Respiratory Activities of Daily Living questionnaire; SD, standard deviation
A significant difference in FEV1 across the three GOLD classifications at both time points (p < 0.001) (Fig. 2) resulted from this intervention. The percentage change indicated the most substantial improvement in participants classified under GOLD stage 4, demonstrating a 23% enhancement between weeks 0 and 4. This was followed by individuals in GOLD stage 3, showing a 15% improvement, and GOLD stage 2, with an 8% improvement. At the 8th week evaluation, the decline in outcomes was notably higher for those in GOLD stage 4, showing a 7% decrease, followed by individuals in GOLD stages 3 and 2, both experiencing a 4% decline. In comparing differences between the active and control groups across the three classifications, participants classified under GOLD stages 2 and 3 exhibited a significant difference (p < 0.001) at both the 4th and 8th weeks. A statistically significant difference at the 4th and 8th weeks in participants with GOLD stage 4 (p < 0.001) at the 4th week and a difference of 0.002 at the 8th week.
Fig. 2: Graph showing changes in the FEV1 as per GOLD stages throughout the 8-week intervention
The changes observed in FVC measures displayed significant differences at week 0 when comparing all three groups based on their GOLD classification of p = 0.039. A notable difference was also observed at week 4, although with a slightly less significance (p = 0.049) (Fig. 3). The percentage improvement was more prominent for GOLD stage 3 exhibiting a 21% improvement, followed by 17% for GOLD stage 4 and 15% for GOLD stage 2. However, from weeks 4 to 8, there was a decline of 7% for participants with a GOLD stage 3 and 6% for participants in GOLD stages 2 and 4. No statistically significant difference was reported at the 8th week (p = 0.056). Upon analyzing outcomes between the control and active groups with each GOLD classification, significant improvements were observed for the active group in GOLD stage 2 both at 4th week (p < 0.001) and 8th week (p = 0.008). Participants with GOLD stage 3 only demonstrated significant improvements at the 4th week (p = 0.005), while no significant improvements were noted in participants with a GOLD stage of 4.
Fig. 3: Graph showing changes in FVC as per GOLD stages throughout the 8-week intervention
Results for FEV1/FVC measures were not significantly different when comparing the three groups. An improvement of 14% for those classified as stage 2 and 15% for those in GOLD stages 3 and 4 at the 4th week was observed, with a consistent percentage decline of 4% observed for all groups at the 8th week timepoint. Analyzing the active and control groups for participants with a GOLD stage of 3 resulted in statistically significant difference of p < 0.001 at the 4th and 8th week, which was not observed in the GOLD stage groups of 2 and 4.
Similarly, in chest measurements, no statistically significant differences were observed. However, participants with a GOLD stage of 3 exhibited differences between both groups at the 4th week for inspiration at the 4th intercostal space (p = 0.003) and at the 10th intercostal space on inspiration (p = 0.037). Those with a GOLD stage of 4 showed statistically significant differences at both the 4th and 8th week for chest measurement taken on expiration (p = 0.009 and p = 0.032, respectively).
Same trends were observed for the 6MWD, with no statistically significant difference reported for any of the three GOLD classification groups or when comparing the active and control groups within each group (Fig. 4).
Fig. 4: Graph showing changes in the 6MWD as per GOLD stages throughout the 8-week intervention
When analyzing the MR-ADL results, no statistically significant differences were found when examining the three distinct classification groups. An 8% improvement was noted in participants with GOLD stages 2 and 3, while a 7% improvement was observed for those in GOLD stage 4. Following the 4-week intervention, the decline was least pronounced (1%) in the most severe patients, with a 4% decline for other participants. Statistically significant differences between the active and control groups were observed for individuals with a GOLD stage of 3 at 4th week (p = 0.001) and 8th week (p = 0.030). No significant differences were observed when comparing the three groups for the control group, except in FEV1 measures.
DISCUSSION
Four weeks of MET interventions, resulted in significant improvements in pulmonary function measurements (p < 0.001), chest measurements (p < 0.001), and ADLs (p < 0.001) for the intervention group as reported by Sevasta et al.1 When considering GOLD stage, statistically significant differences were obtained in lung function measures only. No further statistically significant differences were observed when among participants in GOLD stages 2, 3, or 4.
The most substantial improvement in FEV1 measures was reported in individuals classified with COPD classification of four, showing a 23% change from baseline to week 4, compared to 15% in stage 3 COPD and 8% in those classified as stage 2 COPD participants. At the 8th week timepoint, stage 4 patients with COPD experienced a higher decline in FEV1 measures, reaching a 7% decline, compared to 4% decrease observed in stages 2 and 3. With regard to FVC outcome measures, patients with stage 3 COPD showed the most improvement, with a 21% increase, followed by 17% increase in stage 4 and 15% increase in stage 2.
Lung function measures possibly improved because of the differences in muscle structure and weakness present in these patients. More severe COPD patients tend to have fewer type I fibers compared to type II fibers, known as the slow-to-fast-twitch fiber transformation. This transformation is linked to poor lung function, exercise capacity, functional performance, and increase mortality.12 The observed benefits of MET techniques are attributed to their ability to restore the strength of weak muscles, leading to more pronounced benefits in FEV1 and FVC measures, especially in patients with weaker muscles.
Furthermore, the improvements in lung function is associated with the effect METs have on chest wall mechanics and the thoracic spine. Changes in mechanics and vertebral deformities are linked to breathlessness and altered lung function in COPD, exacerbating as the condition worsens. These changes result in rib cage narrowing, lung compression,13 decreased lung contractions, reduced chest muscle activity, and weakened accessory muscles of respiration. Use of accessory muscles of respiration indicates severe disease. This could lead to lead to a decrease in FEV1 of up to 30% from normal.
Single sessions of muscle stretching have been reported to enhance the extensibility of soft tissues by impacting the contractile properties of muscles and inducing viscoelastic changes in the muscle-tendon unit.13 These authors highlight that immediate stress relaxation in muscles was noted after stretching sessions, accompanied by reduced myoelectric activity. Conducting a 4-week intervention allowed for more pronounced improvements in the most affected muscles, contributing to enhancements in lung function measures, sustained for an extended duration due to substantial changes in muscle structure. Increased muscle flexibility leads to decreased rigidity in the chest wall and positions the accessory muscles closer to their optimal length, ultimately improving mechanical efficiency.14
These findings are promising and warrant further investigations involving larger sample groups to assess the impact of METs on lung function measures. Baxter et al.14 reported no effect of manual therapy on lung function. However, preliminary findings from smaller studies indicate potential enhancements in vital capacity and inspiratory capacity, necessitating further investigation. On the other hand, Cruz-Montecinos et al.15 reported improved lung function following MET applications to accessory muscles of respiration but in conjunction with other manual therapy techniques.16
Notably, other outcomes, including those showing statistically significant improvements (chest wall measurements and ADL scores) did not exhibit differences related to disease severity.
CONCLUSION
Four weeks of METs resulted in more marked improvements in lung function among more severe patients diagnosed with COPD (stages 3 and 4), whereas no substantial improvements were observed in chest measurements, ADLs, or exercise tolerance tests, when examining the different GOLD stage groups.
ORCID
Tonio P Agius https://orcid.org/0000-0002-7490-4438
Kimberley Sevasta https://orcid.org/0000-0002-9646-498X
Anabel Sciriha https://orcid.org/0000-0002-9704-0273
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