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Before major athletic events, a taper is often prescribed to facilitate recovery and enhance performance. However, it is unknown which taper model is most effective for peaking maximal strength and positively augmenting skeletal muscle. Thus, the purpose of this study was to compare performance outcomes and skeletal muscle adaptations following a step vs. an exponential taper in strength athletes. Sixteen powerlifters (24.0 ± 4.0 years, 174.4 ± 8.2 cm, 89.8 ± 21.4 kg) participated in a 6-week training program aimed at peaking maximal strength on back squat [initial 1-repetition-maximum (1RM): 174.7 ± 33.4 kg], bench press (118.5 ± 29.9 kg), and deadlift (189.9 ± 41.2 kg). Powerlifters were matched based on relative maximal strength, and randomly assigned to either (a) 1-week overreach and 1-week step taper or (b) 1-week overreach and 3-week exponential taper. Athletes were tested pre- and post-training on measures of body composition, jumping performance, isometric squat, and 1RM. Whole muscle size was assessed at the proximal, middle, and distal vastus lateralis using ultrasonography and microbiopsies at the middle vastus lateralis site. Muscle samples ( = 15) were analyzed for fiber size, fiber type [myosin-heavy chain (MHC)-I, -IIA, -IIX, hybrid-I/IIA] using whole muscle immunohistochemistry and single fiber dot blots, gene expression, and microRNA abundance. There were significant main time effects for 1RM squat ( < 0.001), bench press ( < 0.001), and deadlift, ( = 0.024), powerlifting total ( < 0.001), Wilks Score ( < 0.001), squat jump peak-power scaled to body mass ( = 0.001), body mass ( = 0.005), fat mass ( = 0.002), and fat mass index ( = 0.002). There were significant main time effects for medial whole muscle cross-sectional area (mCSA) ( = 0.006) and averaged sites ( < 0.001). There was also a significant interaction for MHC-IIA fiber cross-sectional area (fCSA) ( = 0.014) with comparisons revealing increases following the step-taper only ( = 0.002). There were significant main time effects for single-fiber MHC-I% ( = 0.015) and MHC-IIA% ( = 0.033), as well as for MyoD ( = 0.002), MyoG ( = 0.037), and miR-499a ( = 0.033). Overall, increases in whole mCSA, fCSA, MHC-IIA fCSA, and MHC transitions appeared to favor the step taper group. An overreach followed by a step taper appears to produce a myocellular environment that enhances skeletal muscle adaptations, whereas an exponential taper may favor neuromuscular performance.

Travis, SK, Mujika, I, Zwetsloot, KA, Gentles, JA, Stone, MH, and Bazyler, CD. The effects of 3 vs. 5 days of training cessation on maximal strength. J Strength Cond Res 36(3): 633-640, 2022-The purpose of this study was to compare the effects of 3 vs. 5 days of training cessation on body composition, perceived recovery and stress state, and maximal strength. Nineteen strength-trained athletes (23.8 ± 4.1 year; 90.8 ± 20.7 kg; 174.2 ± 7.3 cm) completed a powerlifting specific 4-week training block followed by either 3 or 5 days of training cessation. During the 4-week training block, athletes were trained 3 days per week, performing 3-4 movements that included at least 2-3 competition lifts per session while performing 4-5 sets of 3-5 repetitions with intensity ranging from 75 to 100% 1 repetition maximum (1RM). Body composition, psychometric measures, upper-body maximal strength, and lower-body maximal strength were assessed before (T1) and after 4 weeks of training (T2) and at 3 or 5 days of training cessation (T3). The alpha level was set at p < 0.05. After the 4-week training block (T1 to T2), trivial significant increases in body mass (p = 0.016, Hedge's g = 0.04) and bench press 1RM (p = 0.01, g = 0.16) were observed, as well as small significant increases in back squat 1RM (p < 0.001, g = 0.23), deadlift 1RM (p = 0.003, g = 0.20), powerlifting total (p < 0.001, g = 0.21), and Wilks Score (p < 0.001, g = 0.27). There were no significant differences between groups for isometric back squat performance, psychometric measures, and body composition after training cessation (T2-T3). However, small significant decreases in isometric bench press performance were observed after 5 days (p < 0.001, g = 0.16), but not 3 days of training cessation. The results of this study suggest maximal lower-body strength can be preserved during 3 and 5 days of training cessation, but maximal upper-body strength is only preserved for 3 days after 4 weeks of strength training in athletes.

Travis, SK, Pritchard, HJ, Mujika, I, Gentles, JA, Stone, MH, and Bazyler, CD. Characterizing the tapering practices of United States and Canadian raw powerlifters. J Strength Cond Res 35(12S): S26-S35, 2021-The purpose of this study was to characterize the tapering practices used by North American powerlifters. A total of 364 powerlifters completed a 41-item survey encompassing demographics, general training, general tapering, and specific tapering practices. Nonparametric statistics were used to assess sex (male and female), competition level (regional/provincial, national, and international), and competition lift (squat, bench press, and deadlift). The highest training volume most frequently took place 5-8 weeks before competition, whereas the highest training intensity was completed 2 weeks before competition. A step taper was primarily used over 7-10 days while decreasing the training volume by 41-50% with varied intensity. The final heavy (>85% 1 repetition maximum [1RM]) back squat and deadlift sessions were completed 7-10 days before competition, whereas the final heavy bench press session was completed <7 days before competition. Final heavy lifts were completed at 90.0-92.5% 1RM but reduced to 75-80% 1RM for back squat and bench press and 70-75% for deadlift during the final training session of each lift. Set and repetition schemes during the taper varied between lifts with most frequent reports of 3 × 2, 3 × 3, and 3 × 1 for back squat, bench press, and deadlift, respectively. Training cessation durations before competition varied between deadlift (5.8 ± 2.5 days), back squat (4.1 ± 1.9 days), and bench press (3.9 ± 1.8 days). Complete training cessation was implemented 2.8 ± 1.1 days before competition and varied between sex and competition level. These findings provide novel insights into the tapering practices of North American powerlifters and can be used to inform powerlifting coaches and athlete's tapering decisions.

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<p>Chronic resistance training leads to muscle hypotrophy in a wide range of populations however most resistance training studies are relatively small in sample size</p> <p>Three studies were conducted to better understand the sources of this variability. The first study employed a unilateral resistance training model to test the effects of relative training load and volume on the magnitude of hypertrophy and strength gains. This study showed that high relative training loads were no better than low training loads at inducing muscle hypertrophy provided that each set was performed to the point of muscular exhaustion. In agreement with previous finding, strength gains were greatest with the highest loads.</p> <p>The next two studies attempted to correlate various putative regulators of muscle hypertrophy with the magnitude of hypertrophy after 16 weeks of training in 23 subjects. Study two showed no association between the acute responses of testosterone, GH or IGF-1 and muscle hypertrophy but did show associations with androgen receptor content and acute phosphorylation of p70S6K. This suggests that local rather than systemic processes are the most important regulators of muscle hypertrophy.</p> <p>The third study tested whether the acute post exercise protein synthetic response to a single bout of resistance exercise is related to the magnitude of hypertrophy following training in the same subjects. Although previous work has shown that acute post exercise protein synthetic response is qualitatively similar to the magnitude of hypertrophy after chronic training with similar manipulations in different subjects, we did not see any relationship.</p> / Doctor of Philosophy (PhD)

Introduktion: Långvarigt stillasittande och repetitivt arbete har visat på negativa kroppsliga effekter som till exempel muskuloskeletala besvär och ökad risk för hjärt-kärlsjukdomar. Som motvikt finns evidens för att variation under arbetsdagen i form av korta, aktiva pauser ger positiva effekter där så lite som två minuter styrketräning per dag räcker. Att implementera aktiva pauser är dock utmanande och flera faktorer spelar in både hos medarbetare och chefer.  Syfte: Syftet är att undersöka prevalensen av muskuloskeletal smärta före och efter implementering av aktiva styrkepauser, i form av fysisk aktivitet under arbetstid, på Klinik A. Studien ska även undersöka deltagandet och attityden till implementeringen av aktiva styrkepauser på klinik A, B och C.  Metod: Uppföljning av implementering av aktiva styrkepauser infördes på tre avdelningar på ett större sjukhus. Medarbetarna på avdelningarna fick en enkät, utformad av författarna, utskickad via mail som frågade om deltagande och attityd av implementeringen. En avdelning besvarade ytterligare en enkät om muskuloskeletal smärta. Denna enkät var en ett-årsuppföljning mellan oktober 2022 och oktober 2023.  Resultat: Resultatet från besvärsenkäten visade att muskuloskeletala besvär i nacke, axlar och övre rygg minskade efter ett år. Implementeringsenkäten visade att det var 30 av 32 som deltog i de aktiva styrkepauserna. Deltagarna hade en positiv attityd och upplevelse av implementeringen. Stöttning från chefer och starka individuella motivationsfaktorer, såsom tävlingsmoment, visade sig vara viktiga aspekter.   Konklusion: Den minskade muskuloskeletala smärtan stämmer överens med andra studier. Majoriteten av de som svarade på implementeringsenkäten deltog i de aktiva pauserna och hade en positiv attityd till de aktiva styrkepauserna. Mer forskning i olika arbetsmiljöer krävs dock för att säkerställa hur en lyckad implementering av aktiva styrkepauser ska genomföras.

<p>The aims of this study were to investigate the mechanisms underlying (1) the ageing-related motor handicap at the whole muscle, cellular, contractile protein and myonuclear levels; and (2) ageing-related differences in muscle adaptability.</p><p>In vivo muscles function was studied in the knee extensors. Decreases were observed in isokinetic and isometric torque outputs in old age in the sedentary men and women and elite master sprinters. A 20-week long specific sprint and resistance training successfully improved the maximal isometric force and rate of force development in a subgroup of master sprinters.</p><p>In vitro measurements were performed in muscle biopsies from the vastus lateralis muscle. Immunocytochemical and contractile measurements in single membrane permeabilized muscle fibres demonstrated ageing- and gender-related changes at the myofibrillar level. In sedentary subjects, data showed a preferential decrease in the size of muscle fibres expressing type IIa MyHC in men, lower force generating capacity in muscle fibres expressing the type I MyHC isoform in both men and women and lower maximum velocity of unloaded shortening (V₀) in fibres expressing types I and IIa MyHC isoforms in both men and women. The master sprinters also experienced the typical ageing-related reduction in the size of fast-twitch fibres, a shift toward a slower MyHC isoform profile and a lower V₀ of type I MyHC fibres, which played a role in the decline in explosive force production capacity. The fast-twitch fibre area increased after the resistance training period. A model combining single muscle fibre confocal microscopy with a novel algorithm for 3D imaging of myonuclei in single muscle fibre segments was introduced to study the spatial organisation of myonuclei and the size of individual myonuclear domains (MNDs). Significant changes in the MND size variability and myonuclear organization were observed in old age, irrespective gender and fibre type. Those changes may influence the local quantity of specific proteins per muscle fibre volume by decreased and/or local cooperativity of myonuclei in a gender and muscle fibre specific manner.</p><p>In conclusion, the ageing-related impairments in in vivo muscle function were related to significant changes in morphology, contractile protein expression and regulation at the muscle fibre level. It is suggested that the altered myonuclear organisation observed in old age impacts on muscle fibre protein synthesis and degradation with consequences for the ageing-related changes in skeletal muscle structure and function. However, the improved muscle function in response to a 20-week intense physical training regime in highly motivated physically active old subjects demonstrates that all ageing-related in muscle function are not immutable.</p>