The isometric mid-thigh pull (IMTP) has been cited often in the scientific literature; however, there is still a lack of agreement as to the ideal body position used during this test, and how body position impacts the relationship between IMTP performance and dynamic performance. Thus, one aim of this dissertation was to compare two different IMTP positions and correlate the kinetic outputs from each position to vertical jump (VJ) performance. Another purpose of this dissertation was analyze which method of data normalization for IMTP force variables best correlates to squat jump (SJ) and countermovement jump (CMJ) performance. In the first study, subjects presented higher force outputs for an upright position (hip angles 145°, knee 125°) when compared to a bent position (hip angles 125°, knee 125°). However, there were no statistical differences among correlations from the two positions when correlating to VJ performance. Thus, we suggest that the upright position should be the one used for research and monitoring due to higher force values presented. The second part of this study was to compare correlations from non-normalized and normalized data from the IMTP to SJ and CMJ. Besides non-normalized data, five common methods of normalization were used – subtracting the body mass force, dividing the forces per body mass, allometric scale, scaling by height (Ford’s scale) and scaling by Sinclair coefficient value. In general, higher value correlations were presented with the non-normalized methods for both jumps – SJ and CMJ. Therefore, when using IMTP data to correlate with VJ performance, there is no need to normalize the data.

The purposes of this dissertation were to 1) determine what tapering and peaking practices appear to be most effective via systematic review, 2) to identify the tapering and peaking practices used by North American powerlifters, 3) to experimentally compare muscular adaptations and performance changes following two different training cessation periods, and 4) to experimentally compare the two most common taper models following a training program aimed at peaking maximal strength. Based on the scientific literature, a step and exponential taper appeared to be the most effective tapering models used when volume-load is reduced by half over 2±1 week. Interestingly, North American powerlifters reported that the step taper was most often used while reducing volume-load by 41-50% over 7-10 days. Furthermore experimentally, there were no changes in lower body maximal strength following 3 or 5 days of training cessation. However, upper body maximal strength decreased following 5 days of training cessation. Thus, at the end of a taper, a training cessation period of 3 days appears to be effective for maintaining upper and lower body maximal strength. Furthermore, a work-matched step taper and exponential taper produced similar outcomes for 1RM back squat, bench press, and deadlift, powerlifting total and Wilks Score in strength athletes, yet deadlift 1RM changes favored the exponential taper. However, there were clear physiological differences observed at the whole muscle and muscle fiber levels that appeared to contribute to performance outcomes. This was one of the first investigations demonstrating whole muscle and muscle fiber hypertrophy following a peaking program in strength athletes. Immunohistochemical and immunoblotting analyses demonstrated an increase in myosin-heavy chain IIA content with concomitant decreases in myosin-heavy chain I and IIX content, particularly following the step-taper. These myosin isoform shifts towards a faster, higher quality phenotype were related to changes in underlying myocellular signaling (i.e. Sox6 upregulation, micro RNA-499a downregulation) responsible for fiber-type transitions. These findings indicate a shorter taper may produce favorable muscular adaptations followed by a period of short-term training cessation to prevent the loss of taper-induced performance adaptations. Overall, the findings from these investigations support the use of tapering to enhance maximal strength.

The purpose of this dissertation was to evaluate the effects of changing body position on the execution of the isometric mid-thigh pull (IMTP). Furthermore, while there is evidence to suggest that there is an effect of familiarization on performance of maximal strength tests, there has been no known research evaluating the effect of learning on the IMTP. The effect of familiarization was assessed by evaluating changes in variables obtained from the IMTP. Subjects did not statistically improve over the five IMTP testing sessions, regardless of the body position used, or if subjects had previous experience with weightlifting derivatives. This may indicate that little familiarization is needed for subjects to perform the IMTP before acute increases due to learning stabilize. When body positions were compared, there were differences in force production whether subjects had or did not have experience with weightlifting movements. The magnitude of difference between body position was affected by weightlifting movement experience; lifters with >6 months experience with weightlifting had larger differences in force production between position. Average muscle activation for a variety of muscles, evaluated with surface EMG, appeared to differ between body positions, although these positions are idiosyncratic to experience level. In particular, lumbar erector spinae activation was higher in the bent position for both groups, which may have implications for low back injury risk.In entirety, it appears that if maximizing force production is the goal, the upright positon is optimal. Furthermore, the differing body positions have meaningfully different effects on how 3 much individual muscles are activated between positions. Lastly, substantial familiarization does not appear to be necessary before subjects perform the IMTP.

The purpose of this study was to compare differences in maximal strength, perceived recovery and stress state, and body composition alterations in powerlifters undergoing a 2-day or 4-day period of training cessation following a step taper. Ten participants completed a 6-week powerlifting specific training protocol. Body composition, perceived recovery and stress state, and maximal strength in the back squat (BS), bench press (BP), and deadlift (DL) were assessed prior to the overreach week (week 5) and either 2-days or 4-days after the taper. Alpha criterion was set at p≤0.05. There were statistically significant increases in BP (pp=0.03) following the 2-day protocol. Following the 4-day protocol, there were statistically significant increases in DL (p=0.03) and statistically significant decreases in BP (p=0.04). The results of this study support the use of shorter periods of training cessation (i.e., two days) following a step taper to improve maximal strength performance.

No description available.

The main aim of this thesis was to examine hamstrings anatomy and its influence on knee flexor muscle function in healthy young men. A secondary aim was to better understand the implications of hamstrings anatomy and function, and their variability, in relation to the risk of strain injury. The functional and conventional H:Q ratios (examined up to high angular velocities) as well as the knee joint angle-specific isometric H:Q ratio exhibited good test-retest reliability at joint positions that closely replicated the conditions of high injury risk. Football players did not exhibit any differences in angle-specific or peak torque H:Q ratios compared to recreationally active controls. Knee extensor and flexor strength, relative to body mass, of footballers and controls was similar for all velocities, except concentric knee flexor strength at 400° s-1 (footballers +40%; P < 0.01). Muscle volume explained 30-71% and 38-58% of the differences between individuals in knee extensors and flexors torque respectively across a range of velocities. A moderate correlation was also found between the volume of these antagonistic muscle groups (R2= 0.41). The relative volume of the knee extensors and flexors explained ~20% of the variance in the isometric H:Q ratio and ~31% in the high velocity functional H:Q ratio. Biceps femoris long head exhibited a balanced myosin heavy chain isoform distribution (47.1% type I and 52.9 % total type II) in young healthy men, while BFlh muscle composition was not related to any measure of knee flexor maximal or explosive strength. Biceps femoris long head proximal aponeurosis area varied considerably between participants (>4-fold) and was not related to biceps femoris long head maximal anatomical cross-sectional area (r= 0.04, P= 0.83). Consequently, the aponeurosis:muscle area ratio exhibited 6-fold variability (range, 0.53 to 3.09; CV= 32.5%). Aponeurosis size was not related to isometric or eccentric knee flexion strength. The findings of this thesis suggest that the main anatomical factor that contributes to knee flexors function in vivo is hamstrings muscle size, while muscle composition and aponeurosis size do not seem to have a significant influence. The high inter-individual variability of the biceps femoris long head proximal aponeurosis size suggests that a disproportionately small aponeurosis may be a risk factor for strain injury. In contrast, biceps femoris long head muscle composition does not seem to explain the high incidence of strain injuries in this muscle. Quadriceps and hamstrings muscle size imbalances contribute to functional imbalances that may predispose to strain injury and correction of any size imbalance may be a useful injury prevention tool. Finally, regular exposure to football training and match-play does not seem to influence the balance of muscle strength around the knee joint.

Submitted by FLAVIANE POLETO DE OLIVEIRA null (fla_vb13@hotmail.com) on 2018-03-24T13:04:27Z No. of bitstreams: 1 Dissertação de mestrado_Flaviane Poleto_versão definitiva.pdf: 677650 bytes, checksum: b1dd23673956cadc620d339f8764038f (MD5) / Approved for entry into archive by Claudia Adriana Spindola null (claudia@fct.unesp.br) on 2018-03-26T12:39:15Z (GMT) No. of bitstreams: 1 oliveira_fp_me_prud.pdf: 677650 bytes, checksum: b1dd23673956cadc620d339f8764038f (MD5) / Made available in DSpace on 2018-03-26T12:39:15Z (GMT). No. of bitstreams: 1 oliveira_fp_me_prud.pdf: 677650 bytes, checksum: b1dd23673956cadc620d339f8764038f (MD5) Previous issue date: 2018-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O Treinamento Concorrente (a combinação de exercício aeróbio com treinamento de força) pode resultar em uma interferência negativa no desempenho de força. Além disso, há indicações de que a magnitude dessa interferência é dependente do modo/intensidade do exercício aeróbio. OBJETIVO: Sendo assim, o objetivo deste estudo foi comparar o efeito agudo do Treinamento de Força (TF) e do Treinamento Concorrente (TC) consistidos do Treinamento Intermitente de Alta Intensidade (HIIT) sob os ganhos de força máxima e volume durante 12 semanas. MÉTODOS: A amostra foi composta por 19 homens recreativamente ativos divididos entre o grupo TC (n=11) e grupo TF (n=8). O grupo TC realizou o HIIT (1min de corrida a 100% da velocidade aeróbia máxima intercalado por 1min de recuperação passiva até atingir 5 km) e em seguida uma sessão de treinamento de força constituída por oito exercícios com cargas de 8-12 repetições máximas, enquanto o grupo TF realizou apenas as sessões de treinamento de força. Ambos os grupos treinavam duas vezes por semana durante 12 semanas. A força máxima e o volume de treinamento durante uma sessão aguda foram avaliados pré, após oito e 12 semanas de treinamento. RESULTADOS: Um pequeno efeito de interferência foi observado na força máxima em relação à massa corporal após 12 semanas de treinamento com maiores melhorias no grupo TF quando comparado ao grupo TC. A mesma não foi observada após oito semanas de treinamento. CONCLUSÃO: Esses resultados sugerem que o volume realizado não exerceu impacto nos ganhos de força até oito semanas de treinamento concorrente constituído por HIIT. / The concurrent training (i.e., combination of endurance with strength training) may result in negative interference on strength performance. Moreover, there are indications that the magnitude of this interference is dependent on endurance exercise mode. PURPOSE: The purpose of this study was to compare maximal strength gains and acute volume performed during strength training (ST) and concurrent training (CT) consisting of high-intensity intermittent training plus strength training over the course of a 12-week intervention. METHODS: Nineteen recreationally active males were divided in CT (n=11) and ST (n=8) groups. The CT group performed repeated 1 min efforts at 100% of maximal aerobic velocity interspersed by 1 min of passive recovery until accumulating a total running distance of 5km followed by a strength session (consisting of three sets of eight exercises with loads of 8-12 repetition maximum) twice weekly for a period of 12 weeks, while the ST group performed only strength training sessions. Maximal strength and training volume during an acute exercise session were evaluated at baseline and after eight and 12 weeks of training. A two-way analysis of variance (group and training period) with repeated measures in the second factor was conducted to compare maximal strength values. A three-way analysis of variance (group, training period and set) was conducted to compare the volume performed in the acute exercise sessions. RESULTS: A small interference effect was observed in maximal strength relative to body mass after 12 weeks of training with greater improvements in the ST group compared to the CT group, that were not observed after 8 weeks. The volume performed during the acute exercise session was lower in CT than ST after 8 and 12 weeks of training. In summary, executing high-intensity intermittent exercise before strength training impaired the total volume performed after 8 and 12 weeks compared with strength training alone but the impairment of maximal strength occurred only after 12 weeks. CONCLUSION: These results suggest that the impairment of volume performed did not have an impact on strength gains until after 8 weeks of concurrent training with high-intensity intermittent exercise.

L’optimisation de la performance oblige l’athlète à répéter des séances d’entraînement à haute intensité de travail avec peu de récupération, ce qui génère une fatigue neuromusculaire qui peut être préjudiciable. Ainsi, dans le but de limiter ce phénomène et d’améliorer l’efficacité des séances d’entraînement, le choix d’une récupération adéquate s’impose.La récupération active est la méthode la plus connue et la plus efficace relatée dans la littérature. En effet, de nombreuses études démontrent son effet bénéfique sur la fatigue provoquée lors d’exercices globaux (types course ou pédalage). Cette modalité de récupération correspond à un exercice musculaire léger permettant une augmentation du flux sanguin périphérique et une élimination plus rapide des métabolites. A l’heure actuelle, peu d’études se sont intéressées à la récupération active appliquée de manière locale pour des exercices de renforcement de groupes musculaires spécifiques.L’objectif de ce travail était donc d’étudier la méthode la plus efficace, en termes de modalité et de moment d’application, pour récupérer la force maximale de l’athlète lors d’un exercice de renforcement musculaire. De plus, afin d’assurer une application de cette récupération active, spécifiquement sur les groupes musculaires souhaités, nous avons utilisé l’électromyostimulation (EMS).Nos différents résultats suggèrent qu’il n’est pas nécessaire d’appliquer une modalité particulière pour la récupération des exercices de renforcement musculaire réalisés à intensité maximale. En effet, la récupération active par EMS appliquée au cours d’une séance (entre les séries) ou après une séance ne montre pas de différence avec une récupération passive. De plus, l’application proximale ou distale de l’EMS n’a pas d’influence sur la cinétique de récupération. L’approche neuromusculaire de la fatigue, montre cependant, qu’il s’avère nécessaire d’analyser l’origine des perturbations engendrées par l’exercice, afin de choisir la modalité de récupération la mieux adaptée / The high frequency of resistance training sessions induces heavy strain and fatigue phenomenon, which could be prejudicial for subsequent performance. In this context, it appears necessary to apply proper recovery strategies in order to improve the athlete’s ability to regain an adequate working state for subsequent training.Active recovery is widely described in the literature as the most efficient method for this purpose. It consists in low-intensity exercises, which could improve metabolites washout by increasing peripheral blood flow. To our knowledge, active recovery is usually applied globally, with exercises involving the whole body (light pedalling or running) but little is known regarding a local application after analytical exercises such as strengthening exercise. The aim of our research was therefore to determine the most effective method to recover from resistance training session in terms of maximal strength performance. Among the active recovery modes, electromyostimulation (EMS) is of particular interest since it can be applied on specific muscles groups. Our results showed that active recovery using EMS applied during a session (between the sets) or after a session, did not demonstrate any difference as compared with passive recovery. Also, we demonstrated that EMS was not more efficient when applied distally. However, we highlighted that the investigation of neuromuscular parameters is necessary to better understand the origin of the fatigue induced by a specific exercise in order to apply the most appropriated recovery mode

Purpose: The purpose of our investigation was to compare repetition maximum (RM) to relative intensity using sets and repetitions (RISR) resistance training (RT) on measures of training load, vertical jump, and force production in well-trained lifters. Methods: Fifteen well-trained (isometric peak force= 4403.61+664.69 N, mean+SD) males underwent RT 3 d·wk-1 for 10-weeks in either an RM group (n=8) or RISR group (n=7). Weeks 8-10 consisted of a tapering period for both groups. The RM group achieved a relative maximum each day while the RISRgroup trained based on percentages. Testing at five time-points included unweighted ( Results: Moderate between-group effect sizes were observed for all SJ and CMJ conditions supporting the RISR group (g=0.76-1.07). A small between-group effect size supported RISR for allometrically-scaled isometric peak force (g=0.20). Large and moderate between-group effect sizes supported RISR for rate of force development from 0-50ms (g=1.25) and 0-100ms (g=0.89). Weekly volume load displacement was not different between groups (p>0.05), however training strain was statistically greater in the RM group (p<0.05). Conclusions: Overall, this study demonstrated that RISR training yielded greater improvements in vertical jump, rate of force development, and maximal strength compared to RM training, which may partly be explained by differences in the imposed training stress and the use of failure/non-failure training in a well-trained population.

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.