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Warneke K, Behm DG, Alizadeh S, Hillebrecht M, Konrad A, Wirth K. Discussing Conflicting Explanatory Approaches in Flexibility Training Under Consideration of Physiology: A Narrative Review. Sports Med 2024; 54:1785-1799. [PMID: 38819597 PMCID: PMC11258068 DOI: 10.1007/s40279-024-02043-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2024] [Indexed: 06/01/2024]
Abstract
The mechanisms underlying range of motion enhancements via flexibility training discussed in the literature show high heterogeneity in research methodology and study findings. In addition, scientific conclusions are mostly based on functional observations while studies considering the underlying physiology are less common. However, understanding the underlying mechanisms that contribute to an improved range of motion through stretching is crucial for conducting comparable studies with sound designs, optimising training routines and accurately interpreting resulting outcomes. While there seems to be no evidence to attribute acute range of motion increases as well as changes in muscle and tendon stiffness and pain perception specifically to stretching or foam rolling, the role of general warm-up effects is discussed in this paper. Additionally, the role of mechanical tension applied to greater muscle lengths for range of motion improvement will be discussed. Thus, it is suggested that physical training stressors can be seen as external stimuli that control gene expression via the targeted stimulation of transcription factors, leading to structural adaptations due to enhanced protein synthesis. Hence, the possible role of serial sarcomerogenesis in altering pain perception, reducing muscle stiffness and passive torque, or changes in the optimal joint angle for force development is considered as well as alternative interventions with a potential impact on anabolic pathways. As there are limited possibilities to directly measure serial sarcomere number, longitudinal muscle hypertrophy remains without direct evidence. The available literature does not demonstrate the necessity of only using specific flexibility training routines such as stretching to enhance acute or chronic range of motion.
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Affiliation(s)
- Konstantin Warneke
- Institute of Human Movement Science, Sport and Health, University of Graz, Graz, Austria.
- Department of Movement Sciences, Institute of Sport Science, University of Klagenfurt, Universitatsstraße 65, 9020, Klagenfurt Am Wörthersee, Austria.
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada.
| | - David G Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Shahab Alizadeh
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
- Human Performance Lab, Department of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Martin Hillebrecht
- University Sports Center, Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Andreas Konrad
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
- University Sports Center, Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Klaus Wirth
- University of Applied Sciences Wiener Neustadt, Vienna, Austria
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Wohlann T, Warneke K, Kalder V, Behm DG, Schmidt T, Schiemann S. Influence of 8-weeks of supervised static stretching or resistance training of pectoral major muscles on maximal strength, muscle thickness and range of motion. Eur J Appl Physiol 2024; 124:1885-1893. [PMID: 38240811 PMCID: PMC11129965 DOI: 10.1007/s00421-023-05413-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 12/29/2023] [Indexed: 05/28/2024]
Abstract
OBJECTIVES Current research suggests static stretch-induced maximal strength increases and muscle hypertrophy with potential to substitute resistance-training routines. However, most studies investigated the plantar flexors. This study explored the effects of a static stretching program on maximal strength, hypertrophy and flexibility of the pectoralis major and compared the effects with those of traditional resistance training. METHODS Eighty-one (81) active participants were allocated to either a static stretching, strength-training or control group. Pectoralis stretching was applied 15 min/day, 4 days per week for 8 weeks, while resistance training trained 3 days per week, 5 × 12 repetitions. RESULTS There was an increase in all parameters (strength: p < 0.001, ƞ2 = 0.313, muscle thickness: p < 0.001, ƞ2 = 0.157-0.264, flexibility: p < 0.001, ƞ2 = 0.316) and a time*group interaction (strength: p = 0.001, ƞ2 = 0.154, muscle thickness: p = 0.008-0.001, ƞ2 = 0.117-0.173, flexibility: p < 0.001, ƞ2 = 0.267). Post-hoc testing showed no difference between both intervention groups regarding maximal strength and muscle thickness (p = 0.905-0.983, d = 0.036-0.087), while flexibility increased in the stretching group (p = 0.001, d = 0.789). CONCLUSION Stretching showed increases in maximal strength and hypertrophy, which were comparable with commonly used resistance training. Based on current literature, the influence of mechanical tension as the underlying mechanism is discussed. Furthermore, as equipment and comparatively long stretching durations are requested to induce meaningful strength increases in recreationally active participants, practical application seems limited to special circumstances.
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Affiliation(s)
- Tim Wohlann
- Institute for Exercise, Sport and Health, Leuphana University, Lüneburg, Germany.
- Institute of Sport Science, University of Oldenburg, Oldenburg, Germany.
| | - Konstantin Warneke
- Institute of Sport Science, Alpen-Adria-University Klagenfurt, Klagenfurt Am Wörthersee, Austria
| | - Vincent Kalder
- Institute of Sport Science, University of Oldenburg, Oldenburg, Germany
| | - David G Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Tobias Schmidt
- Department of Sport Science, Medical School Hamburg, Hamburg, Germany
| | - Stephan Schiemann
- Institute for Exercise, Sport and Health, Leuphana University, Lüneburg, Germany
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Warneke K, Lohmann LH, Behm DG, Wirth K, Keiner M, Schiemann S, Wilke J. Effects of Chronic Static Stretching on Maximal Strength and Muscle Hypertrophy: A Systematic Review and Meta-Analysis with Meta-Regression. SPORTS MEDICINE - OPEN 2024; 10:45. [PMID: 38637473 PMCID: PMC11026323 DOI: 10.1186/s40798-024-00706-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 03/26/2024] [Indexed: 04/20/2024]
Abstract
BACKGROUND Increases in maximal strength and muscle volume represent central aims of training interventions. Recent research suggested that the chronic application of stretch may be effective in inducing hypertrophy. The present systematic review therefore aimed to syntheisize the evidence on changes of strength and muscle volume following chronic static stretching. METHODS Three data bases were sceened to conduct a systematic review with meta-analysis. Studies using randomized, controlled trials with longitudinal (≥ 2 weeks) design, investigating strength and muscle volume following static stretching in humans, were included. Study quality was rated by two examiners using the PEDro scale. RESULTS A total of 42 studies with 1318 cumulative participants were identified. Meta-analyses using robust variance estimation showed small stretch-mediated maximal strength increases (d = 0.30 p < 0.001) with stretching duration and intervention time as significant moderators. Including all studies, stretching induced small magnitude, but significant hypertrophy effects (d = 0.20). Longer stretching durations and intervention periods as well as higher training frequencies revealed small (d = 0.26-0.28), but significant effects (p < 0.001-0.005), while lower dosage did not reach the level of significance (p = 0.13-0.39). CONCLUSIONS While of minor effectiveness, chronic static stretching represents a possible alternative to resistance training when aiming to improve strength and increase muscle size. As a dose-response relationship may exist, higher stretch durations and frequencies as well as long program durations should be further elaborated.
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Affiliation(s)
- Konstantin Warneke
- Institute of Human Movement Science, Sport and Health, University of Graz, Graz, Austria
- Department of Movement Sciences, University of Klagenfurt, Klagenfurt am Wörthersee, Austria
| | - Lars Hubertus Lohmann
- Department of Human Motion Science and Exercise Physiology, Friedrich Schiller University, 07743, Jena, Germany.
| | - David G Behm
- School of Human Kinetics and Recreation, Newfoundland and Labrador, Memorial University of Newfoundland, St. John's, Canada
| | - Klaus Wirth
- University of Applied Sciences Wiener Neustadt, Wiener Neustadt, Austria
| | - Michael Keiner
- Department of Sport Science, German University of Health & Sport, Ismaning, Germany
| | - Stephan Schiemann
- Institute of Exercise, Sport and Health, Leuphana University, Lüneburg, Germany
| | - Jan Wilke
- Department of Movement Sciences, University of Klagenfurt, Klagenfurt am Wörthersee, Austria
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Wohlann T, Warneke K, Behm DG, Schiemann S. Comparison of Supervised versus Self-Administered Stretching on Bench Press Maximal Strength and Force Development. Sports (Basel) 2024; 12:109. [PMID: 38668577 PMCID: PMC11054409 DOI: 10.3390/sports12040109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 04/29/2024] Open
Abstract
PURPOSE While there is reported superior effectiveness with supervised training, it usually requires specialized exercise facilities and instructors. It is reported in the literature that high-volume stretching improves pectoralis muscles strength under supervised conditions while practical relevance is discussed. Therefore, the study objective was to compare the effects of volume equated, supervised- and self-administered home-based stretching on strength performance. METHODS Sixty-three recreational participants were equally assigned to either a supervised static stretching, home-based stretching, or control group. The effects of 15 min pectoralis stretching, 4 days per week for 8 weeks, were assessed on dynamic and isometric bench press strength and force development. RESULTS While there was a large magnitude maximal strength increase (p < 0.001-0.023, ƞ2 = 0.118-0.351), force development remained unaffected. Dynamic maximal strength in both groups demonstrated large magnitude increases compared to the control group (p < 0.001-0.001, d = 1.227-0.905). No differences between the intervention group for maximal strength (p = 0.518-0.821, d = 0.101-0.322) could be detected. CONCLUSIONS The results could potentially be attributed to stretch-induced tension (mechanical overload) with subsequent anabolic adaptations, and alternative explanatory approaches are discussed. Nevertheless, home-based stretching seems a practical alternative to supervised training with potential meaningful applications in different settings.
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Affiliation(s)
- Tim Wohlann
- Institute for Exercise, Sport and Health, Leuphana University, 21335 Lüneburg, Germany; (T.W.)
- University Sports Centre, Carl of Ossietzky University Oldenburg, 26129 Oldenburg, Germany
| | - Konstantin Warneke
- Institute of Movement Science, Sport and Health, Karl-Franzens University Graz, 8020 Graz, Austria
| | - David G. Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7 P.O. Box 4200, Canada;
| | - Stephan Schiemann
- Institute for Exercise, Sport and Health, Leuphana University, 21335 Lüneburg, Germany; (T.W.)
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Behm DG, Granacher U, Warneke K, Aragão-Santos JC, Da Silva-Grigoletto ME, Konrad A. Minimalist Training: Is Lower Dosage or Intensity Resistance Training Effective to Improve Physical Fitness? A Narrative Review. Sports Med 2024; 54:289-302. [PMID: 37924459 PMCID: PMC10933173 DOI: 10.1007/s40279-023-01949-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2023] [Indexed: 11/06/2023]
Abstract
BACKGROUND Findings from original research, systematic reviews, and meta-analyses have demonstrated the effectiveness of resistance training (RT) on markers of performance and health. However, the literature is inconsistent with regards to the dosage effects (frequency, intensity, time, type) of RT to maximize training-induced improvements. This is most likely due to moderating factors such as age, sex, and training status. Moreover, individuals with limited time to exercise or who lack motivation to perform RT are interested in the least amount of RT to improve physical fitness. OBJECTIVES The objective of this review was to investigate and identify lower than typically recommended RT dosages (i.e., shorter durations, lower volumes, and intensity activities) that can improve fitness components such as muscle strength and endurance for sedentary individuals or beginners not meeting the minimal recommendation of exercise. METHODS Due to the broad research question involving different RT types, cohorts, and outcome measures (i.e., high heterogeneity), a narrative review was selected instead of a systematic meta-analysis approach. RESULTS It seems that one weekly RT session is sufficient to induce strength gains in RT beginners with < 3 sets and loads below 50% of one-repetition maximum (1RM). With regards to the number of repetitions, the literature is controversial and some authors report that repetition to failure is key to achieve optimal adaptations, while other authors report similar adaptations with fewer repetitions. Additionally, higher intensity or heavier loads tend to provide superior results. With regards to the RT type, multi-joint exercises induce similar or even larger effects than single-joint exercises. CONCLUSION The least amount of RT that can be performed to improve physical fitness for beginners for at least the first 12 weeks is one weekly session at intensities below 50% 1RM, with < 3 sets per multi-joint exercise.
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Affiliation(s)
- David G Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, A1C 5S7, Canada
| | - Urs Granacher
- Department of Sport and Sport Science Exercise and Human Movement Science, University of Freiburg, Freiburg, Germany
| | - Konstantin Warneke
- Institute for Exercise, Sport and Health, Leuphana University, Lüneburg, Germany
| | - Jose Carlos Aragão-Santos
- Department of Physical Education, Post Graduate Program in Health Sciences, Federal University of Sergipe, São Cristóvão, Brazil
| | - Marzo Edir Da Silva-Grigoletto
- Department of Physical Education, Post Graduate Program in Health Sciences, Federal University of Sergipe, São Cristóvão, Brazil
| | - Andreas Konrad
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, A1C 5S7, Canada.
- Institute of Human Movement Science, Sport and Health, Graz University, Graz, Austria.
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Warneke K, Hillebrecht M, Claassen-Helmers E, Wohlann T, Keiner M, Behm DG. Effects of a Home-Based Stretching Program on Bench Press Maximum Strength and Shoulder Flexibility. J Sports Sci Med 2023; 22:597-604. [PMID: 38045741 PMCID: PMC10690509 DOI: 10.52082/jssm.2023.597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 09/05/2023] [Indexed: 12/05/2023]
Abstract
Recent research showed significant stretch-mediated maximum strength increases when performing stretching between 5 to 120 minutes per day with the calf muscle. However, since the practical applicability of these long stretching durations was questioned and studies exploring the transferability to the upper body are scarce, the aim of this study was to investigate the possibility of using a home-based stretching program to induce significant increases in maximum strength and flexibility. Therefore, 31 recreationally active participants (intervention group: 18, control group: 13) stretched the pectoralis major for 15min/day for eight weeks, incorporating three different stretching exercises. The maximum strength was tested isometrically and dynamically in the bench press (one-repetition maximum: 1RM) as well as shoulder range of motion (ROM) performing bilateral shoulder rotation with a scaled bar. Using a two-way analysis of variance (ANOVA) with repeated measures, the results showed high magnitude Time effects (ƞ² = 0.388-0.582, p < 0.001) and Group*Time interaction (ƞ² = 0.281-0.53, p < 0.001-0.002), with increases of 7.4 ± 5.6% in 1RM and of 9.8 ± 5.0% in ROM test in the intervention group. In the isometric testing, there was a high-magnitude Time effect (ƞ² = 0.271, p = 0.003), however, the Group*Time interaction failed to reach significance (p = 0.75). The results are in line with previous results that showed stretch-mediated maximum strength increases in the lower extremity. Future research should address the underlying physiological mechanisms such as muscle hypertrophy, contraction conditions as well as pointing out the relevance of intensity, training frequency and stretching duration.
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Affiliation(s)
- Konstantin Warneke
- Institute of Sport Science, Alpen-Adria-University Klagenfurt, Klagenfurt, Austria
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Martin Hillebrecht
- University Sports Center, Carl von Ossietzky University, Oldenburg, Germany
| | | | - Tim Wohlann
- University Sports Center, Carl von Ossietzky University, Oldenburg, Germany
| | - Michael Keiner
- Institute of Exercise and Training Science, German University of Health and Sport, Ismaning, Germany
| | - David G Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
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Warneke K, Lohmann LH, Lima CD, Hollander K, Konrad A, Zech A, Nakamura M, Wirth K, Keiner M, Behm DG. Physiology of Stretch-Mediated Hypertrophy and Strength Increases: A Narrative Review. Sports Med 2023; 53:2055-2075. [PMID: 37556026 PMCID: PMC10587333 DOI: 10.1007/s40279-023-01898-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2023] [Indexed: 08/10/2023]
Abstract
Increasing muscle strength and cross-sectional area is of crucial importance to improve or maintain physical function in musculoskeletal rehabilitation and sports performance. Decreases in muscular performance are experienced in phases of reduced physical activity or immobilization. These decrements highlight the need for alternative, easily accessible training regimens for a sedentary population to improve rehabilitation and injury prevention routines. Commonly, muscle hypertrophy and strength increases are associated with resistance training, typically performed in a training facility. Mechanical tension, which is usually induced with resistance machines and devices, is known to be an important factor that stimulates the underlying signaling pathways to enhance protein synthesis. Findings from animal studies suggest an alternative means to induce mechanical tension to enhance protein synthesis, and therefore muscle hypertrophy by inducing high-volume stretching. Thus, this narrative review discusses mechanical tension-induced physiological adaptations and their impact on muscle hypertrophy and strength gains. Furthermore, research addressing stretch-induced hypertrophy is critically analyzed. Derived from animal research, the stretching literature exploring the impact of static stretching on morphological and functional adaptations was reviewed and critically discussed. No studies have investigated the underlying physiological mechanisms in humans yet, and thus the underlying mechanisms remain speculative and must be discussed in the light of animal research. However, studies that reported functional and morphological increases in humans commonly used stretching durations of > 30 min per session of the plantar flexors, indicating the importance of high stretching volume, if the aim is to increase muscle mass and maximum strength. Therefore, the practical applicability seems limited to settings without access to resistance training (e.g., in an immobilized state at the start of rehabilitation), as resistance training seems to be more time efficient. Nevertheless, further research is needed to generate evidence in different human populations (athletes, sedentary individuals, and rehabilitation patients) and to quantify stretching intensity.
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Affiliation(s)
- Konstantin Warneke
- Institute for Exercise, Sport and Health, Leuphana University, Universitätsallee 1, 21335, Lüneburg, Deutschland, Germany.
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada.
- Institute of Sport Science, Alpen-Adria University Klagenfurt, Klagenfurt, Germany.
| | - Lars H Lohmann
- University Sports Center, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Camila D Lima
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Karsten Hollander
- Institute of Interdisciplinary Exercise Science and Sports Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Andreas Konrad
- Institute of Human Movement Science, Sport and Health, University of Graz, Graz, Austria
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Astrid Zech
- Department of Human Motion Science and Exercise Physiology, Friedrich Schiller University, Jena, Germany
| | - Masatoshi Nakamura
- Faculty of Rehabilitation Sciences, Nishi Kyushu University, Ozaki, Kanzaki, Saga, Japan
| | - Klaus Wirth
- Institute of Sport Science, University of Applied Sciences Wiener Neustadt, Wiener Neustadt, Austria
| | - Michael Keiner
- Department of Sport Science, German University of Health and Sport, Ismaning, Germany
| | - David G Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
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