The efficacy of incorporating partial squats in maximal strength training. J Strength Cond Res 28(11): 3024–3032, 2014—The purpose of our study was to examine the effects of 2 different training methods on dynamic and isometric measures of maximal strength. Seventeen recreationally trained men (1 repetition maximum [1RM] squat: 146.9 ± 22.4 kg) were assigned to 2 groups: full range of motion (ROM) squat (F) and full ROM with partial ROM squat (FP) for the 7-week training intervention. Repeated measures analysis of variance revealed that there was a statistically significant group-by-time interaction for impulse scaled at 50, 90, and 250 milliseconds at 90° of knee flexion and rate of force development at 200 milliseconds with 120° of knee flexion (p ≤ 0.05). There was also a statistically significant time effect (p ≤ 0.05) for the 1RM squat, 1RM partial squat, isometric squat peak force allometrically scaled (IPFa) 90°, IPFa 120°, and impulse allometrically scaled at 50, 90, 200, and 250 milliseconds at 90° and 120° of knee flexion. Additionally, the FP group achieved statistically larger relative training intensities (%1RM) during the final 3 weeks of training (p ≤ 0.05). There was a trend for FP to improve over F in 1RM squat (+3.1%, d = 0.53 vs. 0.32), 1RM partial squat (+4.7%, d = 0.95 vs. 0.69), IPFa 120° (+5.7%, d = 0.52 vs. 0.12), and impulse scaled at 50, 90, 200, and 250 milliseconds at 90° (+6.3 to 13.2%, d = 0.50–1.01 vs. 0.30–0.57) and 120° (+3.4 to 16.8%, d = 0.45–1.11 vs. 0.08–0.37). These larger effect sizes in the FP group can likely be explained their ability to train at larger relative training intensities during the final 3 weeks of training resulting in superior training adaptations. Our findings suggest that partial ROM squats in conjunction with full ROM squats may be an effective training method for improving maximal strength and early force-time curve characteristics in men with previous strength training experience. Practically, partial squats may be beneficial for strength and power athletes during a strength-speed mesocycle while peaking for competition.

Effects of short-term free-weight and semiblock periodization resistance training on metabolic syndrome. J Strength Cond Res 30(10): 2682–2696, 2016—The effects of short-term resistance training on performance and health variables associated with prolonged sedentary lifestyle and metabolic syndrome (MS) were investigated. Resistance training may alter a number of health-related, physiological, and performance variables. As a result, resistance training can be used as a valuable tool in ameliorating the effects of a sedentary lifestyle including those associated with MS. Nineteen previously sedentary subjects (10 with MS and 9 with nonmetabolic syndrome [NMS]) underwent 8 weeks of supervised resistance training. Maximum strength was measured using an isometric midthigh pull and resulting force-time curve. Vertical jump height (JH) and power were measured using a force plate. The muscle cross-sectional area (CSA) and type were examined using muscle biopsy and standard analysis techniques. Aerobic power was measured on a cycle ergometer using a ParvoMedics 2400 Metabolic system. Endurance was measured as time to exhaustion on a cycle ergometer. After training, maximum isometric strength, JH, jump power, and V[Combining Dot Above]O2peak increased by approximately 10% (or more) in both the metabolic and NMS groups (both male and female subjects). Over 8 weeks of training, body mass did not change statistically, but percent body fat decreased in subjects with the MS and in women, and lean body mass increased in all groups (p ≤ 0.05). Few alterations were noted in the fiber type. Men had larger CSAs compared those of with women, and there was a fiber-specific trend toward hypertrophy over time. In summary, 8 weeks of semiblock free-weight resistance training improved several performance variables and some cardiovascular factors associated with MS.

Purpose: To determine whether cycle training of sedentary subjects would increase the expression of the principle muscle glucose transporters, six volunteers completed 6 wk of progressively increasing intensity stationary cycle cycling. Methods: In vastus lateralis muscle biopsies, changes in expression of GLUT1, GLUT4, GLUT5, and GLUT12 were compared using quantitative immunoblots with specific protein standards. Regulatory pathway components were evaluated by immunoblots of muscle homogenates and immunohistochemistry of microscopic sections. Results: GLUT1 was unchanged, GLUT4 increased 66%, GLUT12 increased 104%, and GLUT5 decreased 72%. A mitochondrial marker (cytochrome c) and regulators of mitochondrial biogenesis (peroxisome proliferator-activated receptor γ coactivator 1 α and phospho-5′-adenosine monophosphate-activated protein kinase) were unchanged, but the muscle hypertrophy pathway component, phospho-mammalian target of rapamycin (mTOR), increased 83% after the exercise program. In baseline biopsies, GLUT4 by immunohistochemical techniques was 37% greater in Type I (slow twitch, red) muscle fibers, but the exercise training increased GLUT4 expression in Type II (fast twitch, white) fibers by 50%, achieving parity with the Type I fibers. Baseline phospho-mTOR expression was 50% higher in Type II fibers and increased more in Type II fibers (62%) with training but also increased in Type I fibers (34%). Conclusion: Progressive intensity stationary cycle training of previously sedentary subjects increased muscle insulin-responsive glucose transporters (GLUT4 and GLUT12) and decreased the fructose transporter (GLUT5). The increase in GLUT4 occurred primarily in Type II muscle fibers, and this coincided with activation of the mTOR muscle hypertrophy pathway. There was little impact on Type I fiber GLUT4 expression and no evidence of change in mitochondrial biogenesis.

The purpose of this investigation was to study the effects of an 11-week training period performed by female weightlifters. Two weeks before this investigation, baseline measures for total testosterone, cortisol, and testosterone:cortisol ratio were collected. The 11-week training program consisted of the core exercises (i.e., clean, clean and jerk, and snatch) and other supplemental exercises (i.e., clean pull, snatch pull, squat, and front squat). Hormonal, isometric, and dynamic middle thigh pull force-time curve characteristics were assessed biweekly throughout the duration of the investigation, whereas volume load and training intensity were assessed weekly throughout the investigation. The testosterone:cortisol ratio of the baseline (1.19 ± 0.64) was significantly different from the ratio of weeks 1 (0.67 ± 0.36) and 9 (0.94 ± 0.66). When the week-to-week values were compared, week 1 (0.67 ± 0.36) was significantly different (P < 0.05; ηsup>2= 0.84) from week 3 (1.06 ± 0.54). A very strong correlation (r = −0.83; r 2 = 0.69) was found between the percentage change of the testosterone:cortisol ratio and volume load from weeks 1 to 11. Moderate to very strong correlations were noted between the percentage change in volume load and isometric peak force, peak force during the 30% isometric peak force trial, and peak force during the 100-kg trial during the 11 weeks of training. The primary finding of this study was that alterations in training volume load can result in concomitant changes in the anabolic-to-catabolic balance, as indicated by the testosterone:cortisol ratio, and the ability to generate maximal forces.

Acute exposure to vibration has been suggested to produce transient increases in muscular strength (1,2,8), vertical jump displacement (4,8), and power output (2,6,7) recorded while performing various tasks. It has been hypothesized that the reported acute vibration induced increases in performance occur as a result of alterations in neuromuscular stimulation (1,3,4). Specifically, most studies have ascribed the observed improvements to the likeliness of Whole Body Vibration (WBV) in producing a “tonic vibration reflex” (TVR) in which the primary nerve endings of the Ia afferents of the muscle spindle are activated. This is thought to result in the excitation of the alpha-motor neurons and activation of the extrafusal fibers (4) which likely leads to a greater synchronization of motor units as a result of homonymous motor unit contraction. However, not all investigations report improvements in muscular strength (4), vertical jump (7), and power production in response to acute vibration (4). While the current body of scientific knowledge offers conflicting evidence on the effectiveness of WBV in augmenting neuromuscular performance it is possible that WBV may result in alterations to specific aspects of the force-time curve during the performance of a maximal isometric contraction. Therefore, the primary purpose of this investigation was to examine the effects of WBV performed using 30 Hz frequency and 2-4 mm amplitude on the force-time curves of an isometric mid-thigh pull.

No description available.

The purposes of this dissertation were to investigate the acute effects of branched-chain amino acids on psychological, physiological, and subsequent performance changes following high volume resistance training. The rationale for this study design was based on abrupt or contiguous training/ competitions that specific athletes encounter in a competitive season. This study design also sought to fill some gaps in the scientific literature concerning the efficacy of BCAAs for subjective fatigue in a resistance training paradigm. To address the purposes of this dissertation, a one-week study was conducted on resistance trained males, in which half of the subjects were randomly selected to receive BCAAs and the other half was a non-supplement group. The subjects in this study performed two high volume resistance training bouts consisting of squat and bench press (5 sets x 10 repetitions at 95% relative intensity) separated by two days. The physiological variables tested in this study were creatine kinase, interleukin-6, C-reactive protein, testosterone, and cortisol. The performance variables tested in this study were static and counter-movement jumps, isometric mid-thigh pull, and Bosco repeated jumps. The primary findings from this study was that subjects in the BCAA group had a statistically significant decrease in muscle damage, indicated by levels of CK. Additionally, there was a statistically significant increase in T:C ratio for the BCAA group compared to the NS group. Concerning performance variables, BCAAs had a small to moderate effect on rate of force development; however, this result was not statistically significant. There were no differences in psychological variables between the groups. Based on the findings of this dissertation, BCAAs mitigate levels of muscle damage and rate of force development. To conclude, BCAAs may provide a competitive advantage for athletes when training volume and competitions become contiguous.

Stretching is a commonly prescribed exercise activity that has been applied to warm-up, increasing range of motion, and recovery from training. The practitioner should understand the effects of stretching exercise and the inherent differences between types of stretching exercises and activities designed to enhance "looseness" and freedom of motion. Stretching to enhance range of motion may be contraindicated when applied to recovery should be pain-free motion within the constraints of maximum range of motion of a joint.;

Substantial evidence exists regarding how skeletal muscles use energy and how this affects muscular performance. What remains unclear is how characteristics of muscle energetics affect whole-body energetics during daily living, and what effects this may have on mobility. The goal of this study was to determine the associations between muscle and whole-body energetics including the relationships between: 1) muscle PCr depletion (∆PCr) in response to light intensity isotonic contractions and the oxygen deficit at the onset of a 30-min treadmill walk (30MTW), and, 2) muscle oxidative capacity and excess post-exercise oxygen consumption (EPOC; 30MTW), respiratory exchange ratio (RER; 30MTW), and peak oxygen consumption (VO2 peak) from a graded treadmill test. Eight healthy young (28.4 ± 3.5 years) male participants were studied. Muscle energetics were measured via 31-Phosphorus magnetic resonance spectroscopy (31P-MRS). Muscle ∆PCr was determined as the change in PCr during 2-min of isotonic knee extensor contractions. Muscle oxidative capacity was determined as the rate constant (kPCr) of a PCr recovery following 24-s of maximal isokinetic knee extensor contractions. Whole-body energetic responses to the 30MTW were measured via indirect calorimetry. Oxygen deficit and EPOC were determined as the time constants of the change in oxygen consumption at the onset and offset of the 30MTW, respectively. Respiratory exchange ratio was determined as the mean RER during minutes 7-30 (RER L23), 25-30 (RER L5), and 29-30 (RER L1). Peak oxygen consumption was the highest 30-s average of oxygen consumption during a graded treadmill test, normalized to total mass and lean mass measured by dual-X-ray absorptiometry. Spearman rank correlation coefficients (rs) were calculated to evaluate the associations between independent variables (muscle ∆PCr and oxidative capacity) and dependent variables (oxygen deficit, EPOC, RER, and VO2 peak). Muscle ∆PCr had a positive association (rs = 0.46, p = 0.30) with oxygen deficit. Muscle oxidative capacity had a negative association with EPOC (rs = -0.64, p = 0.14), RER L23 (rs = -0.64, p = 0.14), L5 (rs = -0.68, p = 0.11), and L1 (rs = -0.74, p = 0.07). Muscle oxidative capacity had a positive association with VO2 peak per lean mass (rs = 0.64, p = 0.10), but not VO2 peak per total mass (rs = 0.14, p = 0.75). These results provide promising preliminary evidence that muscle energetics are associated with whole-body energetic response to daily-living type exercise.

Die Schwimmer des Deutschen Schwimmverbands verlieren zunehmend den Anschluss an die Weltspitze, was sich in einer sinkenden Anzahl von Medaillen bei internationalen Großereignissen äußert. Als Ursache wurden Mängel im langfristigen Leistungsaufbau identifiziert; in Folge dessen wurden spezifischere Inhalte für das Grundlagenausdauertraining gefordert, um die wettkampfspezifischen Kraftvoraussetzungen besser vorzubereiten. Da gezeigt werden konnte, dass die Atmung im Freistilschwimmen leistungsbegrenzend wirkt, sollte untersucht werden, wie sich durch ein gezieltes Training der Atemmuskulatur bislang ungenutzte Leistungsreserven erschließen lassen. Darüber hinaus sollte die Reaktion auf Hypoventilation unter Belastung getestet werden, da eine Analyse der Atemrhythmen international erfolgreicher Schwimmer ergeben hatte, dass sich niederfrequente Atmung im Wettkampf vorteilhaft auf die Leistung auswirkt. Dazu wurde eine Interventionsstudie mit 15 Nachwuchsschwimmern im Crossover-Design durchgeführt. Während des ersten und des zweiten Makrozyklus des Trainings- und Wettkampfjahres (TWJ) führten je sechs Sportler ein achtwöchiges Atemtraining mit einem POWERbreathe-Gerät durch. Zur Quantifizierung der Leistungsfähigkeit und der Veränderung physiologischer Parameter durch Training wurden vor und nach jeder Intervention Stufentests im Strömungskanal durchgeführt, wobei drei verschiedene Intensitäten und zwei Atemfrequenzen ausgewertet wurden. Das Hauptergebnis der Studie bestand in einer verbesserten Kraftfähigkeit und Ökonomie der Atemmuskulatur, was sich bei isolierter Belastung in Form einer Vergrößerung des maximalen Minutenvolumens zeigte und beim Schwimmen zu verringerten Laktatwerten und niedrigerer Zyklusfrequenz bei gleichbleibender Belastung führte. Die Trainingswirkung wird dabei auf eine weniger starke Ausprägung des inspiratorischen Metaboreflexes und eine Optimierung der Vortriebsphasen in Folge einer schnelleren Inspiration zurückgeführt. Durch das Atemtraining konnte die respiratorische Muskulatur in Trainingsphasen niedrigerer Intensität auf die höheren Belastungen im späteren Verlauf des TWJ vorbereitet werden. Der Einsatz eines solchen Trainings hat daher das Potential, die Leistungsfähigkeit von Freistilschwimmern zu steigern.:Einleitung Theoriepositionen: Anforderungen an die Atmung im Schwimmen Bewegungsstruktur und Atemverhalten im Wettkampf Atemphysiologie unter Belastung Atemtraining Forschungsdefizit Fragestellung Methoden: Arbeitsschwerpunkte und Lösungsweg Pilotstudie im Strömungskanal Hauptuntersuchung Methodenkritik Ergebnisse: Ergebnisse der Voruntersuchungen Auswertung des Atemtrainings Leistungsphysiologische Veränderungen durch Training Einfluss der Intensität auf leistungsphysiologische Parameter Einfluss der Atemfrequenz auf leistungsphysiologische Parameter Zusammenhänge zwischen leistungsphysiologischen Parametern und den Ergebnissen des POWERbreathe-Trainings Diskussion: Wirkung eines lokalen Krafttrainingsreizes auf die Atemmuskulatur und auf pulmonale Parameter Systemische Effekte eines Atemtrainings auf leistungsphysiologische Parameter Konsequenzen einer Atmungseinschränkung für die Energiebereitstellung Wirkung des Atemtrainings auf die Bewegungsstruktur Trainingswissenschaftliche Aspekte Fazit: Empfehlungen für die Durchführung eines Atemtrainings Zukünftige Fragestellungen Zusammenfassung und Ausblick / At present the athletes of the German swimming association are unable to keep up with the performance of the world’s leading swimmers. Thus, the number of medals achieved within international competitions decreases. Analyses could trace back this trend to deficits regarding the long-term athlete development. As a result, there are growing demands on increasing the specificity of the basic endurance training in terms of a more adequate preparation of race-specific strength capacities. Since studies showed that the efficiency of the respiratory system can limit exercise performance, the aim of this dissertation was to analyze the potential of a specific training of the breathing muscles to access reserve capacities in freestyle swimming. An evaluation of the breathing patterns of successful athletes showed that a low-frequency breathing pattern has a positive impact on freestyle performance, hence another goal of this study was to investigate the effect of hypoventilation during high intensity swimming. A crossover intervention study was conducted with 15 adolescent swimmers. During the first and the second macro cycle of the swimming season an eight week POWERbreathe training was performed by six swimmers each. Before and after each intervention incremental tests were conducted in a swimming flume to assess exercise capacity and the change of exercise physiological parameters in response to the training stimulus. Within this test protocol three graded exercise intensities and two different breathing frequencies were taken into account. The main result of the study was an improved strength and enhanced economy of the breathing muscles which resulted in an increased maximum voluntary ventilation (MVV), decreasing levels of lactate and lower cycle frequencies during freestyle swimming at a given velocity. The training effect is based on the attenuation of the inspiratory metaboreflex and optimization of the propulsion phases due to a more rapid inspiration. Because of the breathing training the respiratory muscles were exposed to a high training stimulus within low-intensity swimming training periods which resulted in an improved preparation of higher swimming intensities in the later stages of the swimming season. Thus, the POWERbreathe training has the potential to enhance exercise performance of freestyle swimmers.:Einleitung Theoriepositionen: Anforderungen an die Atmung im Schwimmen Bewegungsstruktur und Atemverhalten im Wettkampf Atemphysiologie unter Belastung Atemtraining Forschungsdefizit Fragestellung Methoden: Arbeitsschwerpunkte und Lösungsweg Pilotstudie im Strömungskanal Hauptuntersuchung Methodenkritik Ergebnisse: Ergebnisse der Voruntersuchungen Auswertung des Atemtrainings Leistungsphysiologische Veränderungen durch Training Einfluss der Intensität auf leistungsphysiologische Parameter Einfluss der Atemfrequenz auf leistungsphysiologische Parameter Zusammenhänge zwischen leistungsphysiologischen Parametern und den Ergebnissen des POWERbreathe-Trainings Diskussion: Wirkung eines lokalen Krafttrainingsreizes auf die Atemmuskulatur und auf pulmonale Parameter Systemische Effekte eines Atemtrainings auf leistungsphysiologische Parameter Konsequenzen einer Atmungseinschränkung für die Energiebereitstellung Wirkung des Atemtrainings auf die Bewegungsstruktur Trainingswissenschaftliche Aspekte Fazit: Empfehlungen für die Durchführung eines Atemtrainings Zukünftige Fragestellungen Zusammenfassung und Ausblick