Search

Additional file 1. Search algorithm, risk of bias assessment for randomized controlled trials and control trials, Grading of Recommendations, Assessment, Development and Evaluations (GRADE) analysis and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist.

This study examined the effects of high-volume static stretching training on gastrocnemius muscle architecture, ankle angle and jump height in 21 female adolescent volleyball players. Static stretching of the plantar flexors of one leg (STR) was performed five times/week for 12 weeks, in addition to volleyball training, with the contra-lateral leg used as control (CON). Total duration of stretching per session increased from 540 s (week 1) to 900 s (week 12). At baseline, week 12 and after 3 weeks of detraining, muscle architecture at the middle and the distal part of both gastrocnemius heads (medialis and lateralis) and ankle angle were examined at rest and at maximum dorsiflexion. At the same time-points gastrocnemius cross-sectional area (CSA) was also assessed, while jumping height was measured at baseline and week 12. Following intervention, ankle dorsiflexion increased in both legs with a greater increase in STR than CON (22 ± 20% vs. 8 ± 17%, p < 0.001). Fascicle length at the middle part of gastrocnemius medialis increased only in the STR, at rest (6 ± 7%, p = 0.006) and at maximum dorsiflexion (11 ± 7%, p < 0.001). Fascicle length at maximum dorsiflexion also increased at the distal part of gastrocnemius lateralis of STR (15 ± 13%, p < 0.001). A greater increase in CSA (23 ± 14% vs. 13 ± 14%, p < 0.001) and in one-leg jumping height (27 ± 30% vs. 17 ± 23%, p < 0.001) was found in STR than CON. Changes in ankle angle, fascicle length and CSA were maintained following detraining. High-volume stretching training for 12 weeks results in ankle dorsiflexion, fascicle length and muscle cross sectional area increases in adolescent female volleyball players. These adaptations may partly explain improvements in jump performance.

This study examined the effects of high-volume static stretching training on gastrocnemius muscle architecture, ankle angle and jump height in 21 female adolescent volleyball players. Static stretching of the plantar flexors of one leg (STR) was performed five times/week for 12 weeks, in addition to volleyball training, with the contra-lateral leg used as control (CON). Total duration of stretching per session increased from 540 s (week 1) to 900 s (week 12). At baseline, week 12 and after 3 weeks of detraining, muscle architecture at the middle and the distal part of both gastrocnemius heads (medialis and lateralis) and ankle angle were examined at rest and at maximum dorsiflexion. At the same time-points gastrocnemius cross-sectional area (CSA) was also assessed, while jumping height was measured at baseline and week 12. Following intervention, ankle dorsiflexion increased in both legs with a greater increase in STR than CON (22 +/- 20% vs. 8 +/- 17%, p < 0.001). Fascicle length at the middle part of gastrocnemius medialis increased only in the STR, at rest (6 +/- 7%, p = 0.006) and at maximum dorsiflexion (11 +/- 7%, p < 0.001). Fascicle length at maximum dorsiflexion also increased at the distal part of gastrocnemius lateralis of STR (15 +/- 13%, p < 0.001). A greater increase in CSA (23 +/- 14% vs. 13 +/- 14%, p < 0.001) and in one-leg jumping height (27 +/- 30% vs. 17 +/- 23%, p < 0.001) was found in STR than CON. Changes in ankle angle, fascicle length and CSA were maintained following detraining. High-volume stretching training for 12 weeks results in ankle dorsiflexion, fascicle length and muscle cross sectional area increases in adolescent female volleyball players. These adaptations may partly explain improvements in jump performance.

Anousaki, E, Zaras, N, Stasinaki A-N, Panidi, I, Terzis, T, and Karampatsos, G. Effects of a 25-week periodized training macrocycle on muscle strength, power, muscle architecture, and performance in well-trained track and field throwers. J Strength Cond Res 35(10): 2728-2736, 2021-The purpose of the study was to investigate the effect of a 25-week macrocycle on strength, power, vastus lateralis (VL) muscle architecture, and competitive track and field throwing performance, in well-trained track and field throwers. Twelve well-trained throwers (age: 24.3 +/- 5.5 years, mass: 96.6 +/- 9.9 kg, and height: 1.82 +/- 0.02 m), participated in the study. All athletes followed a 25-week periodized training program divided into 3 training phases: the hypertrophy/maximum strength phase, the maximum strength/power phase, and the power/speed phase. Measurements were performed at the beginning of the training period (T1), after the first training phase (T2), and after the end of the training period (T3). Measurements included the following: competitive track and field throwing performance; shot put throws; maximum strength (1-RM) in snatch, clean, and squat; countermovement jump (CMJ); and VL muscle architecture. Competitive track and field throwing performance and shot put throws increased from T1 to T3 by 10.9 +/- 3.2% (p = 0.001) and 5.1 +/- 6.4% (P = 0.049), respectively. 1 RM strength in snatch and squat increased significantly from T1 to T3 by 9.7 +/- 8.9% (p = 0.001) and 9.9 +/- 7.1% (p = 0.002), respectively. Countermovement jump height increased only from T1 to T2 by 10.9 +/- 11.8% (p = 0.026). A significant increase was found for VL fascicle length between T1 and T3 (9.6 +/- 11.1%, p = 0.049). Strong correlations were found between the percentage increase of competitive track and field throwing performance with 1 RM snatch (r = 0.571, p = 0.046) and with shot put throws (r = 0.715, p = 0.001). Twenty five weeks of training may increase performance and VL fascicle length, whereas increases in 1 RM snatch and in shot put throws are associated with competitive track and field throwing performance in well-trained throwers.

Σκοπός αυτής της μελέτης ήταν να εξετάσει διαφορές στην αρχιτεκτονική της έσω κεφαλής του γαστροκνημίου, στη μετατόπιση της μυοτενόντιας ένωσης και στο εύρος κίνησης της ποδοκνημικής άρθρωσης, μεταξύ αθλητριών με διαφορετική εμπειρία σε προπόνηση ευκαμψίας. Συγκρίθηκαν οκτώ αθλήτριες ρυθμικής γυμναστικής (ηλικία: 21.9±2.6, προπονητική εμπειρία:11.6±1.3) και οκτώ πετοσφαίρισης (ηλικία: 26.1±4.8, προπονητική εμπειρία:11.8±3.0). Η αρχιτεκτονική δομή στο κεντρικό και στο απομακρυσμένο τμήμα της γαστέρας του μυός, η μετατόπιση της μυοτενόντιας ένωσης και το εύρος κίνησης της ποδοκνημικής, αξιολογήθηκαν σε συνθήκη ηρεμίας και μετά από 1 min διάτασης, μέσω υπερηχογραφικής απεικόνισης και ανάλυσης φωτογραφίας. Σε συνθήκη ηρεμίας, οι αθλήτριες ρυθμικής γυμναστικής είχαν μακρύτερα μυϊκά δεμάτια από τις αθλήτριες πετοσφαίρισης στον κεντρικό (5.91±0.25 vs 4.76±0.32, αντίστοιχα) και στον απομακρυσμένο τομέα του μυός (5.64±o.48 vs 4.61±0.57, αντίστοιχα), μεγαλύτερη γωνία πελματιαίας κάμψης (120.80±4.2 vs 114.29±3.91, αντίστοιχα) και μικρότερη γωνία πρόσφυσης στον κεντρικό τομέα του μυός (22.33±2.62 vs 25.71±2.40, αντίστοιχα) (p