{"doi":"10.1155/2021/8628182","title":"Meta-Analysis of Elderly Lower Body Strength: Different Effects of Tai Chi Exercise on the Knee Joint-Related Muscle Groups","abstract":"<jats:p>Importance. Tai Chi exercise mostly involves muscle fitness with biological, biomechanical, and psychosomatic medicine in elderly rehabilitation. Increased incidents related to elderly muscle fitness deficiency tend to be an urgent public health issue. However, there is a controversy on the effects of Tai Chi exercise on muscle fitness, especially the lower body strength of the elderly. Objective. To determine whether lower body strength such as keen extension and flexion strength may be improved by Tai Chi exercise in older adults from the perspective of evidence-based medicine. Methods. Databases of PubMed, Embase, and Cochrane Library were searched up to July 1, 2021. Randomized clinical trials are adopted to compare Tai Chi exercise with sedentary behavior or other low intensity exercise in terms of influence on lower body strength rehabilitation, especially keen extension and flexion strength in people aged over 60. A meta-analysis was performed to discuss outcomes of lower body strength, knee muscle strength, and knee extension/flexion strength. Results. A total of 25 randomized trials involving 1995 participants fulfilled the inclusion criteria. (1) Tai Chi exercise significantly improved elderly lower body strength (−0.54, [−0.81, −0.28], <jats:inline-formula>\n                     <a:math xmlns:a=\"http://www.w3.org/1998/Math/MathML\" id=\"M1\">\n                        <a:mi>p</a:mi>\n                        <a:mo>&lt;</a:mo>\n                        <a:mn>0.00001</a:mn>\n                     </a:math>\n                  </jats:inline-formula>, I2 = 74%), but there was no differential improvement in the strength of the knee joints (0.10, [−0.02, 0.23], <jats:inline-formula>\n                     <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" id=\"M2\">\n                        <c:mi>p</c:mi>\n                        <c:mo>=</c:mo>\n                        <c:mn>0.11</c:mn>\n                     </c:math>\n                  </jats:inline-formula>, I2 = 34%). (2) Elderly individual lower body strength declined with age, while this trend was suppressed by Tai Chi exercise (−0.35, [0.14, 0.56], <jats:inline-formula>\n                     <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" id=\"M3\">\n                        <e:mi>p</e:mi>\n                        <e:mo>=</e:mo>\n                        <e:mn>0.001</e:mn>\n                     </e:math>\n                  </jats:inline-formula>, I2 = 70%). (3) Although Tai Chi exercise did no significantly improve the large muscle group of knee joint extensor like quadriceps femoris (3.15, [−0.69, 6.99], <jats:inline-formula>\n                     <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" id=\"M4\">\n                        <g:mi>p</g:mi>\n                        <g:mo>=</g:mo>\n                        <g:mn>0.24</g:mn>\n                     </g:math>\n                  </jats:inline-formula>, I2 = 26%), it showed marked enhancement to the strength of deep small muscle group of knee joint flexor (10.25, [6.90, 13.61], <jats:inline-formula>\n                     <i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\" id=\"M5\">\n                        <i:mi>p</i:mi>\n                        <i:mo>&lt;</i:mo>\n                        <i:mn>0.00001</i:mn>\n                     </i:math>\n                  </jats:inline-formula>, I2 = 0%). The heterogeneity might be caused by distinguished measurements of muscle strength. Therefore, Tai Chi exercise specifically enhanced some certain muscle strength of knee joints and improved muscle fitness rehabilitation as well as function activity for elderly. Conclusions. In this RCT meta-analysis, Tai Chi exercise has positive effects on lower body strength of elderly. Although no obvious improvement on the knee extensor is observed, it may be used as a rehabilitation treatment for training stable deep muscle groups to improve the knee flexion strength significantly.</jats:p>","journal":"Evidence-Based Complementary and Alternative Medicine","year":2021,"id":611417,"datarank":0.41588830833596724,"base_score":2.772588722239781,"endowment":2.772588722239781,"self_citation_contribution":0.41588830833596724,"citation_network_contribution":0.0,"self_endowment_contribution":0.41588830833596724,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":15,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1573535,"name":"Jia-hui Li","orcid":null,"position":1,"is_corresponding":false},{"id":1573536,"name":"Nan-Jun Xu","orcid":null,"position":2,"is_corresponding":false},{"id":1573537,"name":"Wei-Yi Yang","orcid":"0000-0001-8657-2269","position":3,"is_corresponding":false},{"id":783560,"name":"Jun Liu","orcid":"0000-0002-8175-6293","position":4,"is_corresponding":false},{"id":592246,"name":"Yuan Yang","orcid":"0000-0002-2914-9832","position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Meta-Analysis of Elderly Lower Body Strength: Different Effects of Tai Chi Exercise on the Knee Joint-Related Muscle Groups","abstract":"<jats:p>Importance. Tai Chi exercise mostly involves muscle fitness with biological, biomechanical, and psychosomatic medicine in elderly rehabilitation. Increased incidents related to elderly muscle fitness deficiency tend to be an urgent public health issue. However, there is a controversy on the effects of Tai Chi exercise on muscle fitness, especially the lower body strength of the elderly. Objective. To determine whether lower body strength such as keen extension and flexion strength may be improved by Tai Chi exercise in older adults from the perspective of evidence-based medicine. Methods. Databases of PubMed, Embase, and Cochrane Library were searched up to July 1, 2021. Randomized clinical trials are adopted to compare Tai Chi exercise with sedentary behavior or other low intensity exercise in terms of influence on lower body strength rehabilitation, especially keen extension and flexion strength in people aged over 60. A meta-analysis was performed to discuss outcomes of lower body strength, knee muscle strength, and knee extension/flexion strength. Results. A total of 25 randomized trials involving 1995 participants fulfilled the inclusion criteria. (1) Tai Chi exercise significantly improved elderly lower body strength (−0.54, [−0.81, −0.28], <jats:inline-formula>\n                     <a:math xmlns:a=\"http://www.w3.org/1998/Math/MathML\" id=\"M1\">\n                        <a:mi>p</a:mi>\n                        <a:mo>&lt;</a:mo>\n                        <a:mn>0.00001</a:mn>\n                     </a:math>\n                  </jats:inline-formula>, I2 = 74%), but there was no differential improvement in the strength of the knee joints (0.10, [−0.02, 0.23], <jats:inline-formula>\n                     <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" id=\"M2\">\n                        <c:mi>p</c:mi>\n                        <c:mo>=</c:mo>\n                        <c:mn>0.11</c:mn>\n                     </c:math>\n                  </jats:inline-formula>, I2 = 34%). (2) Elderly individual lower body strength declined with age, while this trend was suppressed by Tai Chi exercise (−0.35, [0.14, 0.56], <jats:inline-formula>\n                     <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" id=\"M3\">\n                        <e:mi>p</e:mi>\n                        <e:mo>=</e:mo>\n                        <e:mn>0.001</e:mn>\n                     </e:math>\n                  </jats:inline-formula>, I2 = 70%). (3) Although Tai Chi exercise did no significantly improve the large muscle group of knee joint extensor like quadriceps femoris (3.15, [−0.69, 6.99], <jats:inline-formula>\n                     <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" id=\"M4\">\n                        <g:mi>p</g:mi>\n                        <g:mo>=</g:mo>\n                        <g:mn>0.24</g:mn>\n                     </g:math>\n                  </jats:inline-formula>, I2 = 26%), it showed marked enhancement to the strength of deep small muscle group of knee joint flexor (10.25, [6.90, 13.61], <jats:inline-formula>\n                     <i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\" id=\"M5\">\n                        <i:mi>p</i:mi>\n                        <i:mo>&lt;</i:mo>\n                        <i:mn>0.00001</i:mn>\n                     </i:math>\n                  </jats:inline-formula>, I2 = 0%). The heterogeneity might be caused by distinguished measurements of muscle strength. Therefore, Tai Chi exercise specifically enhanced some certain muscle strength of knee joints and improved muscle fitness rehabilitation as well as function activity for elderly. Conclusions. In this RCT meta-analysis, Tai Chi exercise has positive effects on lower body strength of elderly. Although no obvious improvement on the knee extensor is observed, it may be used as a rehabilitation treatment for training stable deep muscle groups to improve the knee flexion strength significantly.</jats:p>","is_dataset_classified":null,"base_score":2.772588722239781,"endowment":2.772588722239781,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"34976101","pmcid":"PMC8716219","openalex_id":"https://openalex.org/W4200525275","authors":[],"funders":[{"funder_name":"National Natural Science Foundation of China","grant_id":"82004383","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"82004386","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"81873314","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"81974574","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"2018M633036","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"B2019091","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"2020A1414050050","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"202102010273","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"[2014]157","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"[2018]8","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"2018KQNCX041","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"YN2019ML08","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"YN2015MS15","title":null}],"total_grants":13,"fwci":0.7571,"citation_percentile":0.62783172,"influential_citations":0,"citation_trend":[{"year":2022,"count":4},{"year":2023,"count":4},{"year":2024,"count":3},{"year":2025,"count":2},{"year":2026,"count":2}],"oa_status":"hybrid","license":"cc-by","oa_locations":[{"url":"https://downloads.hindawi.com/journals/ecam/2021/8628182.pdf","host_type":"journal"},{"url":"https://downloads.hindawi.com/journals/ecam/2021/8628182.pdf","host_type":"publisher"},{"url":"http://downloads.hindawi.com/journals/ecam/2021/8628182.pdf","host_type":"publisher"},{"url":"http://downloads.hindawi.com/journals/ecam/2021/8628182.xml","host_type":"publisher"},{"url":"https://doi.org/10.1155/2021/8628182","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/34976101","host_type":"repository"},{"url":"https://doaj.org/article/36c17594cb3f4a3f9c6338e68d8e3fd5","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/8716219","host_type":"repository"},{"url":"https://europepmc.org/articles/PMC8716219","host_type":"Europe_PMC"},{"url":"https://europepmc.org/articles/PMC8716219?pdf=render","host_type":"Europe_PMC"}],"fields_of_study":["Balance, Gait, and Falls Prevention","Sports injuries and prevention","Musicians’ Health and Performance"],"mesh_terms":[],"keywords":["Medicine","Physical therapy","Randomized controlled trial","Muscle strength","Knee Joint","Strength training","Leg press","Lower body","Rehabilitation","Cochrane Library","Physical medicine and rehabilitation","Meta-analysis","Sarcopenia","Sports medicine","Internal medicine","Surgery"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Good health and well-being"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-01T19:21:10.345706Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}