Monitoring the resistance training volume load (VL) (sets × reps × load) is essential to managing resistance training and the recovery–adaptation process. Subjects: Eight trained weightlifters, seven of which were at national level, participated in the study. Methods: VL was measured both with (VLwD) and without (VL) the inclusion of barbell displacement, across twenty weeks of training, in order to allow for comparisons to be made of these VL calculating methods. This consisted of recording the load, repetition count, and barbell displacement for every set executed. Comparisons were made between VL and VLwD for individual blocks of training, select training weeks, and select training days. Results: Strong, statistically significant correlations (r ≥ 0.78, p < 0.001) were observed between VL and VLwD between all training periods analyzed. t-tests revealed statistically significant (p ≤ 0.018) differences between VL and VLwD in four of the seven training periods analyzed. Conclusion: The very strong relationship between VL and VLwD suggest that a coach with time constraints and a large number of athletes can potentially spare the addition of displacement. However, differences in percent change indicate that coaches with ample time should include displacement in VL calculations, in an effort to acquire more precise workload totals.

This study examined the kinetic and kinematic differences between accentuated eccentric loading (AEL) and cluster sets in trained male subjects (age = 26.1 ± 4.1 years, height = 183.5 ± 4.3 cm, body mass = 92.5 ± 10.5 kg, and back squat to body mass ratio = 1.8 ± 0.3). Four load condition sessions consisted of traditionally loaded (TL) “straight sets,” TL cluster (TLC) sets, AEL cluster (AEC) sets, and AEL “straight sets” where only the first repetition had eccentric overload (AEL1). An interrepetition rest interval of 30 seconds was prescribed for both TLC and AEC. Concentric intensity for all load conditions was 80% 1 repetition maximum (1RM). Accentuated eccentric loading was applied to repetitions using weight releasers with total eccentric load equivalent to 105% of concentric 1RM. Traditionally loaded cluster had statistically greater concentric outputs than TL. Furthermore, statistically greater eccentric and concentric outputs were observed during AEC compared with TL with the exception of peak power. Statistically greater concentric characteristics were observed in TLC compared with AEL1, but statistically greater eccentric outputs were observed in AEL1. In the 2 cluster set conditions, statistically greater concentric rate of force development (RFDCON) (d = 0.470, p < 0.001) and average velocity (vavg) (d = 0.560, p < 0.001) in TLC compared with AEC were observed. However, statistically greater eccentric work (WECC) (d = 2.096, p < 0.001) and eccentric RFD (RFDECC) (d = 0.424, p < 0.001) were observed in AEC compared with TLC. Overall, eccentric overload demonstrated efficacy as a means of increasing eccentric work and RFD, but not as a means of potentiating concentric output. Finally, interrepetition rest seems to have the largest influence on concentric power output and RFD.

The purposes of this investigation were to: (1) assess kinetic characteristics of overload, (2) examine eccentric and concentric muscle activations and (3) explore velocity measurement as a method of intensity prescription in inertial flywheel squat training. A series of two experiments were performed: one assessing kinetic and muscle activation characteristics of flywheel squat training using three progressive inertial loads. The second experiment assessed inertial load-velocity relationships using six progressive inertial loads. Peak force, net impulse, positive–negative impulse ratio and positive–negative impulse duration ratio were each statistically significant between all three load conditions (p < 0.05). Concentric vastus lateralis muscle activation was the only significant increase between inertial loads (p < 0.05). Although not statistically significant, concentric quadricep muscle activation was increased from the lowest to highest inertia. Conversely, eccentric quadricep muscle activation was reduced from the lowest to highest inertia. In the second experiment, statistically significant regression equations were observed for average concentric velocity (R2 = 0.66) and peak concentric velocity (R2 = 0.60). In conclusion, our results indicate (1) overload is possible kinetically, (2) phase-specific muscle activation responds differently to increased inertia and (3) velocity has the potential to be used for load prescription in the inertial flywheel squat.

OBJECTIVE: The main objective of the present study was to assess the association between varying amounts of strength training and insulin resistance. Another goal was to assess the influence of several potential confounding variables on the strength training and insulin resistance relationship. Lastly, the role of waist circumference, fat free mass, and body fat percentage on the association between strength training and insulin resistance was assessed. METHODS: This cross-sectional study included 6561 randomly selected men and women in the US. Data were collected using the precise protocol established by NHANES. HOMA-IR was used as the outcome variable. Both time spent strength training and frequency of strength training bouts were used as exposure variables. RESULTS: There was not a statistically significant relationship between strength training and insulin resistance in women. However, after controlling for 10 potential confounding variables, men who reported no strength training had significantly higher levels of HOMA-IR compared to men who reported moderate or high levels of strength training (F = 9.87, P < 0.0001). Odds ratios were also assessed, and 10 potential confounding variables were controlled. Men reporting no strength training had 2.42 times the odds of having insulin resistance compared to men reporting moderate levels of strength training (95% CI: 1.19 to 4.93). Similarly, men reporting no strength training had 2.50 times the odds of having insulin resistance compared to men reporting high levels of strength training (95% CI: 1.25 to 5.00). CONCLUSION: There was a strong relationship between strength training and insulin resistance in US men, but not in US women. Differences in waist circumference, fat free mass, and body fat percentage, as well as demographic and lifestyle measures, do not appear to mediate the relationship.

The purpose of the current study was two-fold: (1) To examine the variation in velocity and power with increasing intensity in the back squat among subjects; and (2) To explore individual subject characteristics as possible explanations for variations of velocity in the back squat. Fourteen recreationally trained male subjects with experience in the back squat agreed to participate in the study (age = 25.0 ± 2.6 years, height = 178.9 ± 8.1 cm, body mass = 88.2 ± 15.8 kg). One-repetition maximums (1RM) were performed for each subject on force platforms with four linear position transducers attached to the barbell. The 1RM assessment was immediately preceded by warm-up sets at 65%, 75%, 85%, and 95% of estimated 1RM for 5, 3, 2, and 1 repetitions, respectively. Mean concentric velocity (MCV) and mean power were recorded for each intensity condition and were analyzed using Pearson correlation to determine the relationship between each variable and relative intensity (%1RM). Statistically significant negative relationships existed between %1RM and MCV (r = −0.892) and mean power (r = −0.604). Between-subject coefficient of variation tended to increase as %1RM increased for both MCV and mean power. These results suggest that MCV is superior to mean power as an indicator of relative intensity in the back squat. Additionally, the between-subject variation observed at higher intensities for MCV and mean power support the use of velocity ranges by strength and conditioning coaches.

Caffeine is often used in a variety of forms to enhance athletic performance; however, research regarding caffeine’s effects on strength and power in female athletes is lacking. Therefore, the purpose of this study was to analyze the acute effects of caffeine anhydrous (6 mg/kg of body mass) on jumping performance and maximal strength in female collegiate athletes. Eleven athletes (19.7 ± 0.9 yrs; 166.4 ± 10.2 cm, 67.7 ± 9.4 kg) performed two testing sessions separated by one week, and randomly received caffeine or placebo using a double-blind approach. Heart rate, blood pressure, and tympanic temperature were recorded before athletes received each condition, following 60 min of quiet sitting, and directly after performance testing. Athletes were assessed on unweighted and weighted squat jump height (SJH0, SJH20) and countermovement jump height (CMJH0, CMJH20), isometric mid-thigh pull peak force (IPF), and rate of force development from 0–200 ms (RFD200). Resting systolic blood pressure was significantly greater following caffeine administration compared to a placebo (p = 0.017). There were small, significant differences in SJH0 (p = 0.035, g = 0.35), SJH20 (p = 0.002, g = 0.49), CMJH0 (p = 0.015, g = 0.19), and CMJH20 (p < 0.001, g = 0.37) in favor of caffeine over placebo. However, there was no significant difference in IPF (p = 0.369, g = 0.12) and RFD200 (p = 0.235, g = 0.32) between conditions. Therefore, caffeine appears to enhance jumping performance, but not maximal strength in female collegiate athletes.

Orientador: Franciele Marques Vanderlei / Resumo: Estudos sobre o treinamento resistido de baixa intensidade associado à restrição de fluxo sanguíneo (RFS) atualmente tem ganhado destaque, porém ainda existem lacunas que podem ser exploradas em relação aos seus efeitos fisiológicos quando associado a treinamentos excêntricos, principalmente na força e hipertrofia muscular. Objetivo: Realizar uma revisão sistemática com metanálise e um estudo aleatorizado controlado a fim de esclarecer os reais efeitos do TRBI associado à RFS nos desfechos de força, hipertrofia muscular e desempenho funcional, e se a RFS quando associada a treinamentos excêntricos de baixa e alta intensidade é capaz de aumentar as respostas desses desfechos dos extensores de joelho em homens adultos saudáveis. Métodos: A revisão sistemática foi registrada no PROSPERO (número do registro #CRD42018104065). Os estudos foram selecionados por meio de sete bases de dados. Todos os estudos incluídos foram avaliados quanto à qualidade metodológica, utilizando a Escala PEDro, bem como foi avaliada a qualidade da evidência. Somente ensaios clínicos randomizados que avaliaram a eficácia do treinamento com RFS na força e hipertrofia muscular dos músculos extensores de joelho em adultos do sexo masculino, saudáveis e/ou fisicamente ativos, com idade de 18 a 35 anos, contra algum grupo de intervenção foram considerados elegíveis. Todas as metanálises foram conduzidas por meio do software Review Manager – RevMan e descritos como diferenças médias padronizadas (standardized ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Studies on low intensity resistance training associated with blood flow restriction (RFS) are currently gaining prominence, however there are still gaps that can be explored in relation to their physiological effects when associated with eccentric training, especially in muscle strength and hypertrophy. Objective: To carry out a systematic review with meta-analysis and a randomized controlled study in order to clarify the real effects of TRBI associated with RFS on the outcomes of strength, muscle hypertrophy and functional performance, and whether RFS when associated with low and high intensity eccentric training is able to increase the responses of these knee extensor outcomes in healthy adult men. Methods: The systematic review was registered in PROSPERO (registration number # CRD42018104065). The studies were selected through seven databases. All included studies were assessed for methodological quality, using the PEDro Scale, as well as the quality of evidence was assessed. Only randomized controlled trials that assessed the effectiveness of RFS training on muscle strength and hypertrophy of knee extensor muscles in healthy, male and / or physically active adults, aged 18 to 35, against any intervention group were considered eligible. All meta-analyzes were conducted using the Review Manager - RevMan software and described as standardized mean differences (SMD) or mean differences (mean difference - MD) with 95% confidence intervals (CI). The randomized controlled study ... (Complete abstract click electronic access below) / Mestre

Background: Neck pain has a prevalence at 15-30 % in diffrent populations with diffrent causes like whiplash or tension in the muscle. It has proven a positive association between reduced pain and inhibiting the endorphin systems with physical activity. No recent review has been made since 2015, so there was a need to compile recent studies in the field.  Objective: Searches for litterature were made in the databses PubMed, PEDro and CINAHL to find randomized controlled studied that investigated strengthening training of the neck and the thoracal part of the back in persons with neckpain. All of the included articles were appraised by the PEDro-scale and the level of reliability was graded using GRADEstud.  Results: Six studies were included in this review with 382 participants. In one of six studies a significant between group diffrence was seen, the results should be discussed according to the studie's diffrent intervention/control groups. Three studies showed high quality and three showed moderate quality according to PEDro-scale. The grading in evidence showed that strengthening training of the neck and the thoracic back as treament for neckapin has a high level of evidence (++) to not reduce pain according to GRADEstud. The variation in population and time resulted in point deduction for lack of precision.  Conclusion: The results shows that strengthening training of the neck and the thoracic back does not reduce neckpain. Only one of six studied could show a significant between group diffrence. According to GRADEstud a high level of evidence is shown that the treatment dose not give effekt. The results of this study should be drawn with caution due to a low number of studies and the lack of precision in the interventions.

京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第17981号 / 人健博第10号 / 新制||人健||1(附属図書館) / 80825 / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 坪山 直生, 教授 椎名 毅, 教授 松田 秀一 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

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