Unilateral Exercise Research Articles

Differential stimulation of myofibrillar and sarcoplasmic protein synthesis with protein ingestion at rest and after resistance exercise

We aimed to determine whether there is a differential stimulation of the contractile myofibrillar and the cellular sarcoplasmic proteins after ingestion of protein and how this is affected by resistance exercise. Fasted (FAST) muscle protein synthesis was measured in seven healthy young men with a primed constant infusion of L-[ring-(13)C(6)]phenylalanine. Participants then performed an intense bout of unilateral resistance exercise followed by the consumption of 25 g of whey protein to maximally stimulate protein synthesis. In the rested (FED) leg myofibrillar (MYO) protein synthesis was elevated (P < 0.01) above FAST at 3 h (approximately 163%) but not at 1 and 5 h (P > 0.05). In contrast, MYO protein synthesis in the exercised (FED-EX) leg was stimulated above FAST at 1, 3 and 5 h (approximately 100, 216, and 229%, respectively; P < 0.01) with the increase at 5 h being greater than FED (P < 0.01). Thus, the synthesis of muscle contractile proteins is stimulated by both feeding and resistance exercise early (1 h) but has a greater duration and amplitude after resistance exercise. Sarcoplasmic (SARC) protein synthesis was similarly elevated (P < 0.01) above FAST by approximately 104% at 3 h in both FED and FED-EX suggesting SARC protein synthesis is stimulated by feeding but that this response is not augmented by resistance exercise. In conclusion, myofibrillar and sarcoplasmic protein synthesis are similarly, but transiently, stimulated with protein feeding. In contrast, resistance exercise rapidly stimulates and sustains the synthesis of only the myofibrillar protein fraction after protein ingestion. These data highlight the importance of measuring the synthetic response of specific muscle protein fractions when examining the effects of exercise and nutrition.

Measuring synthesis rates of different proteins – clues to training adaptations

Over the past 15–20 years several laboratories have been investigating the regulation of muscle protein synthesis by diet and exercise. It is clear that resistance exercise stimulates muscle protein synthesis. The greatest stimulation comes from resistance exercise plus a source of amino acids (for review see Tipton & Ferrando, 2008). Interestingly, similar increases in muscle protein synthesis are observed following endurance exercise (Tipton et al. 1996); protein ingestion also enhances this response (Howarth et al. 2009). Given the differences in adaptations to these types of exercise, this similarity of response of muscle protein synthesis may seem somewhat paradoxical. The explanation may lie in the methodology. The response of mixed muscle protein synthesis was determined in these studies (Tipton & Ferrando, 2008). Measurement of mixed muscle protein synthesis is essentially a weighted average of the rates of synthesis of all proteins in the muscle, i.e. it does not distinguish the responses of different proteins. Intuitively, given the differences in adaptations to different types of training, it is not difficult to accept that resistance and endurance exercise, for example, should differentially influence different proteins. Recent advances in methodology have allowed us to begin to address these questions. The acute response to exercise and nutritional interventions may be measured and extrapolated to represent the potential for long-term adaptive changes. Adaptations to any exercise training regime result from changes in the type, quantity and activity of proteins in various tissues. For example, muscle growth in response to resistance exercise training is determined by increases in the myofibrillar proteins. Muscle protein synthesis rate has been shown to be predictive of long-term changes in muscle (Tipton, 2008). For example, a recent metabolic study demonstrated that milk ingestion resulted in greater muscle protein synthesis than soy following resistance exercise (Wilkinson et al. 2007). A follow-up longitudinal study by the same research group demonstrated that milk supplementation resulted in greater increases in muscle mass and strength than soy supplements (Hartman et al. 2007). Thus, it is clear that the acute metabolic response to various exercise and nutritional combinations is a useful way to determine optimal training and diet regimes. The results of a study published in this issue of The Journal of Physiology by Moore et al. (2009) offer interesting and important advances toward our understanding of the influence of nutrition and exercise on different types of proteins. This study helps pave the way for future studies that will further our understanding of training adaptations. Moore et al. (2009) used a unilateral exercise model to simultaneously measure protein synthesis rates in response to whey protein ingestion at rest and following resistance exercise. Moreover, the time course of the response to each was determined. The results demonstrate a differential response of the two protein types to feeding. The rate of sarcoplasmic protein synthesis was increased following protein ingestion to the same extent in both the resting and the exercised leg. On the other hand, myofibrillar protein synthesis was increased to a greater extent and the response lasted longer in the exercised leg. These novel findings illustrate that the response of proteins to exercise and nutrition is not uniform. Moreover, and perhaps more importantly, these results underline the value of measuring the response of various protein fractions to nutritional and exercise interventions. The present study examined the response only to resistance exercise (Moore et al. 2009). However, another recent study by this research group provides additional information on differential responsiveness of various protein fractions. Wilkinson et al. (2008) report that myofibrillar protein synthesis and mitochondrial protein synthesis rates both increased in response to resistance exercise. Only mitochondrial protein synthesis increased in response to endurance exercise. Furthermore, exercise training changed these responses (Wilkinson et al. 2008). These data were gathered with a background of hyperaminoacidaemia for all conditions, so the interactive effect of exercise type and nutrition on the different types of protein could not be determined. Clearly, these types of studies provide us with the ability to investigate the potential for exercise and nutrition to influence training results. Further investigation of the impact of different types of exercise on the synthesis of different protein fractions and the interaction with nutritional interventions must follow. Furthermore, studies should delineate responses in various populations. These studies will provide important information for athletes practicing various types of sports. More importantly, these types of studies will offer information critical to designing optimal nutrition and exercise interventions to diminish muscle wasting and metabolic disease.

Great Power Politics and the Structure of Foreign Relations Law

Foreign relations law serves as an internal constraint on the unilateral exercise of foreign relations powers through the distribution of authority within the national government. Given the predominance of the executive branch in foreign affairs, courts routinely resolve questions regarding the breadth of the executive’s authority by reference to the Constitution, legal precedent, historical practice, and functional considerations. Though courts generally focus on these domestic factors, they have been historically quite sensitive to the international political implications of their decisions. But we don’t have a clear understanding of how or when courts consider international politics in resolving foreign relations law questions. We lack a framework to begin thinking about the relationship between international politics and the allocation of decisionmaking authority. This short Article frames foreign relations law as a function of international politics to explore the relationship between the strength of external international political constraints on a state and the levels of judicial deference to the executive in that state. Variation in the structure of international politics— bipolar, multipolar or unipolar—likely produces variation in the strength of external constraints on a state. This approach yields a simple descriptive claim and a related predictive claim. The stronger the external constraints on a state, such as the constraints present in multi-polar or bipolar worlds, the greater the likelihood of judicial deference to the executive on institutional competency grounds. Conversely, the weaker the external constraints on a state, such as the constraints present in a unipolar world, the lesser the likelihood of judicial deference to the executive. If this claim is accurate, it leads to a predictive claim that the rate of judicial deference to the executive will likely decrease as long as the United States is the hegemon of a unipolar world. This approach also provides a clearer picture of the overall level of constraint on the executive, helps describe the impact of external constraints on judicial deference, and explores the effects of international politics on the US’s engagement with international law.

Resistance Exercise Increases Postprandial Muscle Protein Synthesis in Humans

We examined the impact of an acute bout of resistance-type exercise on mixed muscle protein synthesis in the fed state. After a standardized breakfast, 10 untrained males completed a single, unilateral lower-limb resistance-type exercise session. A primed, continuous infusion of l-[ring-C6]phenylalanine was combined with muscle biopsy collection from both the exercised (Ex) and the nonexercised (NEx) leg to assess the impact of local muscle contractions on muscle protein synthesis rates after food intake. Western blotting with phosphospecific and pan antibodies was used to determine the phosphorylation status of AMP-activated kinase (AMPK), 4E-binding protein (4E-BP1), mammalian target of rapamycin (mTOR), and p70 ribosomal protein S6 kinase (S6K1). Muscle protein synthesis rates were approximately 20% higher in Ex compared with NEx (0.098% +/- 0.005% vs 0.083% +/- 0.002%.h, respectively, P < 0.01). In the fed state, resistance-type exercise did not elevate AMPK phosphorylation. However, the phosphorylation status of 4E-BP1 was approximately 20% lower after cessation of exercise in Ex compared with NEx (P < 0.05). Conversely, 4E-BP1 phosphorylation was significantly higher in Ex compared with NEx after 6 h of recovery (P < 0.05) with no changes in mTOR phosphorylation. S6 phosphorylation was greater in Ex versus NEx after cessation of exercise (P < 0.05), although S6K1 phosphorylation at T was not up-regulated (P > 0.05). We conclude that resistance-type exercise performed in a fed state further elevates postprandial muscle protein synthesis rates, which is accompanied by an increase in S6 and 4E-BP1 phosphorylation state.

Unipolarity, State Behavior, and Systemic Consequences

The United States emerged from the 1990s as an unrivaled global power to become a “unipolar” state. This extraordinary imbalance has triggered global debate. Governments and peoples around the world are struggling to understand to how an American-centered unipolar system operates—and to respond to it. What is the character of domination in a unipolar distribution? To what extent can a unipolar state translate its formidable capabilities into meaningful influence? Will a unipolar world be built around rules and institutions or be based more on the unilateral exercise of unipolar power? Scholars too are asking these basic questions about unipolarity and international relations theory. The individual contributions develop hypotheses and explore the impact of unipolarity on the behavior of the dominant state, on the reactions of other states, and on the properties of the international system. Collectively, they find that unipolarity does have a profound impact on international politics. international relations under conditions of unipolarity force a rethinking of conventional and received understandings about the operation of the balance of power, the meaning of alliance partnerships, the logic of international economic cooperation, the relationship between power and legitimacy, and the behavior of satisfied and revisionist states.

Unilateral grip fatigue reduces short interval intracortical inhibition in ipsilateral primary motor cortex

Objective This study was designed to examine whether exhaustive grip exercise of the left hand affected intracortical excitability in ipsilateral motor cortex. Methods Ten healthy male subjects (aged 21–24 years) participated in experiment 1 in which paired-pulse transcranial magnetic stimulation (TMS) was used to test corticospinal and corticocortical excitability in right (relaxed) first dorsal interosseous (FDI) muscle during the recovery period after exhaustive forceful grip exercise of the left hand. Seven of the same subjects participated in experiment 2, in which the intensity of the test stimulus was adjusted so that the amplitude of motor evoked potential (MEP TEST) was kept constant throughout the measurement. Results In experiment 1, MEP TEST was slightly reduced from 5 to 15 min after exercise whilst short interval intracortical inhibition (SICI) at interstimulus interval (ISI) of 2 and 3 ms became less effective. Intracortical facilitation (ICF) was unchanged. In experiment 2 when the MEP TEST was maintained at a constant size there was again no change in ICF, and the reduction in SICI was still present at the same intervals. Conclusions We conclude that unilateral exhaustive grip exercise reduced the excitability of the corticospinal output of the ipsilateral motor cortex whilst simultaneously reducing the excitability of SICI. These results would be compatible with the idea that fatigue increases the tonic level of interhemispheric inhibition from the fatigued to the non-fatigued cortex. Significance Muscle fatigue to the point of exhaustion has lasting effects on the excitability of intracortical circuits in the non-exercised hemisphere, perhaps via changes in the tonic levels of activity in transcallosal pathways.

Developing the Publicness of Public International Law: Towards a Legal Framework for Global Governance Activities

This paper develops a comprehensive framework for the legal analysis of global governance phenomena. Global governance is considered as an important analytical perspective which points out new trends in relations. However, from a normative standpoint it is unsatisfactory, as it does not allow to single out those activities of institutions which compromise individual self-determination. To this end, the paper proposes the concept of international public authority, which allows identifying all hard and soft mechanisms that constitute unilateral exercises of power. For such unilateral, public power to be legitimate, it needs to correspond to yet to be defined standards of public law. After discussing current legal approaches like Global Administrative Law and constitutionalism, which all aim at the development of such standards, the paper proposes a comprehensive public law approach, which finds its basis in institutional law. This approach would avoid the uncertainties surrounding the legal bases of principles of Global Administrative Law and the risk of constitutionalism to fail on its normative ambitions. The paper sets out the framework of a comprehensive research project on the exercise of public authority by institutions.

Resistance exercise increases postexercise oxygen consumption in nonexercising muscle

This study examined the effect of knee extension resistance exercise on muscle oxygen consumption in nonexercising forearm flexor muscles (nonexV(O)(2mus)) after exercise. Seven healthy male subjects were performed six sets of unilateral knee extension exercise until exhaustion at 40, 60, and 80% of 1 repetition maximum (RM) on separate days. The nonexV(O)(2mus) values at rest, at the end of exercise, and during recovery after exercise were measured by near-infrared spectroscopy. The nonexV(O)(2mus) at the end of exercise was significantly (P < 0.05) increased by 1.8 +/- 0.2, 1.7 +/- 0.2, and 1.4 +/- 0.3 fold over resting value at 40, 60 and 80% 1RM, respectively. NonexV(O)(2mus) returned to the resting values after 1-5 min of recovery and then showed no further significant change for all exercise intensities. This study suggests that knee extension resistance exercise at 40, 60 and 80% 1RM induced an increase in nonexV(O)(2mus) and that the increase of nonexV(O)(2mus) after exercise returned to resting value in several minutes.

Resistance exercise decreases eIF2Bε phosphorylation and potentiates the feeding-induced stimulation of p70S6K1 and rpS6 in young men

We investigated the effect of resistance exercise and feeding on the activation of signaling proteins involved in translation initiation. Nine young men (23.7+/-0.41 yr; BMI=25.5+/-1.0 kg/m2; means+/-SE) were tested twice after they performed a strenuous bout of unilateral resistance exercise, such that their contralateral leg acted as a nonexercised comparator, in either the fasted and fed [1,000 kJ, each 90 min (3 doses): 10 g protein, 41 g carbohydrate, 4 g fat] states. Muscle biopsies were obtained 6 h postexercise from both legs, resulting in four experimental conditions: rest-fasted, rest-fed, exercise-fasted, and exercise-fed. Feeding increased PKB/Akt (Ser473) phosphorylation (P<0.05), while exercise increased the phosphorylation of Akt and the downstream 70 kDa S6 protein kinase (p70S6K1, Thr389) and ribosomal protein S6 (rpS6, Ser235/236, Ser240/244; all P<0.05). The combination of resistance exercise and feeding increased the phosphorylation of p70S6K1 (Thr389) and rpS6 (Ser240/244) above exercise alone (P<0.05). Exercise also reduced phosphorylation of the catalytic epsilon subunit of eukaryotic initiation factor 2B (eIF2Bepsilon, Ser540; P<0.05). Mammalian target of rapamycin (mTOR, Ser2448), glycogen synthase kinase-3beta (GSK-3beta, Ser9), and focal adhesion kinase (FAK, Tyr576/577) phosphorylation were unaffected by either feeding or resistance exercise (all P>0.14). In summary, feeding resulted in phosphorylation of Akt, while resistance exercise stimulated phosphorylation of Akt, p70S6K1, rpS6, and dephosphorylation eIF2Bepsilon with a synergistic effect of feeding and exercise on p70(S6K1) and its downstream target rpS6. We conclude that resistance exercise potentiates the effect of feeding on the phosphorylation and presumably activation of critical proteins involved in the regulation of muscle protein synthesis in young men.

Reduced contribution of the ipsilateral primary motor cortex to force modulation with short-term motor learning in humans: An NIRS study

AbstractHow is muscle force modulated during hand exercise? Oxygenation in the contralateral primary motor cortex (M1) has been observed to vary considerably across trials of repetitive handgrip exercise. No linear relationship was observed between the average value of oxygenation determined by a block design study and the force of the handgrip. We found reduced oxygenation in the ipsilateral M1 and unchanged oxygenation in the contralateral M1 during repetitive static handgrip exercises (40% and 60% maximal voluntary contraction; 10 s exercise/75 s rest; 5 sets), which might be due to short-term motor learning. These results support the hypothesis that the ipsilateral M1 might functionally compensate for the contralateral M1 in force modulation during unilateral exercises.

The Influence of Bar Diameter on Neuromuscular Strength and Activation: Inferences from an Isometric Unilateral Bench Press

The purpose of this study was to examine the influence of two different bar diameters on neuromuscular activation and strength. The bar diameters used reflected a standard Olympic bar (28 mm (1.1 inch); THIN) and a larger fat bar (51 mm [2 inch]; THICK). Eighteen healthy men (age 25.0 +/- 1 years) were assessed for their maximal voluntary contraction (MVC) during a unilateral isometric bench press exercise with the 2 bar types at 2 different joint angles (angle 1 and angle 2; elbow joint at approximately 45 and 90 degrees , respectively). Additionally, on a separate day, subjects performed three 10-second isometric repetitions at an intensity of 80% MVC using the 2 different bars at angle 1 and angle 2. Electromyographic recordings were collected in the pectoralis major and the muscles of the forearm flexor region at a sampling rate of 1000 Hz during the second day of testing. Analysis of variance was used to examine differences in MVC between bars and also examine between bar differences in electromyographic activity for each muscle group at each joint angle. A significance level of 0.05 was used for all tests. MVC was not different between bar types, although there was a main effect of joint angle on MVC such that it was greater at angle 2. There was a main effect of bar at both angles for the forearm muscles and at angle 1 for the pectoralis such that electromyographic activity was greater with THIN. Our data do not support the hypothesis that bar diameter influences performance during an isometric bench press exercise. However, higher electromyographic activity with THIN suggests greater neuromuscular activation with a standard Olympic bar as opposed to a larger diameter "fat" bar. Although our data do not support the use of a fat bar for increasing neuromuscular activation, these findings should be confirmed in other resistance training exercises.

Muscle Tissue Oxygenation and Force Production during Low-intensity Resistance Exercise with Blood Flow Restriction

We have recently demonstrated that an acute bout of low-intensity resistance exercise combined with blood flow restriction (Kaatsu exercise) stimulates both muscle protein synthesis and translation initiation. Recently, myocardial ischemia-reperfusion has also been shown to activate the signaling pathway of translation initiation. PURPOSE: To investigate the changes in muscle tissue oxygenation during Kaatsu exercise to assess the level of ischemia-reperfusion condition in skeletal muscle. METHODS: Six subjects performed three separate experiments randomly; Control (CON), Kaatsu (KAT, blow restriction via pressure cuff), or High-intensity (HI) exercise group. CON and KAT performed a bout of unilateral knee extension exercise at 20% of 1-repetition maximum (1-RM) strength, while HI group exercised at 70% 1-RM. Vastus lateralis and rectus femoris muscle tissue oxygenation (HbO2) was assessed using near-infrared spectroscopy (NIRS), and isometric muscle strength was assessed immediately before and after the exercise bout. RESULTS: In the KAT, resting HbO2 was reduced significantly (rest, 61.7%; cuff, 54.5%; p<0.05) in response to blood flow restriction. During exercise, HbO2 decreased further in KAT and reached the same level of tissue oxygenation as HI (KAT, 45.6%; HI, 44.8%; p<0.05 vs. rest for both groups) whereas HbO2 did not change in CON. During the recovery period, HbO2 was restored to the resting level both in CON and HI group (63.9 and 69.1% for CON and HI, respectively), whereas it was still significantly depressed in KAT group (51.4%, p<0.05). Muscular strength was significantly reduced after the bout of exercise in KAT and HI (-45 and -25% for KAT and HI, respectively; p<0.05), whereas no change in strength was observed in CON (-1.8%). CONCLUSION: Although a decreased tissue oxygenation during exercise and recovery period may contribute to muscle fatigue, sustained ischemic condition during recovery period in KAT suggests a non-significant ischemia-reperfusion during low intensity resistance exercise with blood flow restriction.

Controlling the Unilateral Exercise of Intellectual Property Rights: A Multitude of Approaches But No Way Ahead? The Transatlantic Search for a New Approach

The complex interface between intellectual property law and law is currently under review both in the US and the EU. One field of contention is the unilateral exercise of intellectual property rights. This paper presents the different approaches recently taken by different US courts, critically reviews the ECJ's jurisprudence in the much-debated decisions Magill and IMS Health and discusses the test proposed by the EU Commission in its Discussion Paper on Exclusionary Abuses, finding that none of the approaches has addressed the problem convincingly so far. In searching for a way ahead, the paper attempts to systematize the different positions taken in the literature, contrasting in particular an law approach and a competition law approach. It argues that a pure law popular in the US, is not fully applicable in the EU where IP law remains national and must respect the supremacy of the EU rules which must be applied uniformly in all Member States. Other theories which strive to take both IP and law rationales into account - e.g. Heinemann's scope of reward-theory - leave open the criteria on the basis of which this shall be done. The most promising approach, then, may be to shift back attention towards policy rationales and to focus on the concept of contestable markets, as by Heinemann and Drexl have recently proposed. The threshold for antitrust intervention must, however, remain high. The three criteria used in the telecommunications sector to decide when regulation is justified may be of help to determine cases of legitimate intervention.

Cross-Transfer Effects of Resistance Training with Blood Flow Restriction

This study investigated whether muscle hypertrophy-promoting effects are cross-transferred in resistance training with blood flow restriction, which has been shown to evoke strong endocrine activation. Fifteen untrained men were randomly assigned into the occlusive training group (OCC, N = 8) and the normal training group (NOR, N = 7). Both groups performed the same unilateral arm exercise (arm curl) at 50% of one-repetition maximum (1RM) without occlusion (three sets, 10 repetitions). Either the dominant or nondominant arm was randomly chosen to be trained (OCC-T, NOR-T) or to serve as a control (OCC-C, NOR-C). After the arm exercise, OCC performed leg exercise with blood flow restriction (30% of 1RM, three sets, 15-30 repetitions), whereas NOR performed the same leg exercise without occlusion. The training session was performed twice a week for 10 wk. In a separate set of experiments, acute changes in blood hormone concentrations were measured after the same leg exercises with (N = 5) and without (N = 5) occlusion. Cross-sectional area (CSA) and isometric torque of elbow flexor muscles increased significantly in OCC-T, whereas no significant changes were observed in OCC-C, NOR-T, and NOR-C. CSA and isometric torque of thigh muscles increased significantly in OCC, whereas no significant changes were observed in NOR. Noradrenaline concentration showed a significantly larger increase after leg exercise with occlusion than after exercises without occlusion, though growth hormone and testosterone concentrations did not show significant differences between these two types of exercises. The results indicate that low-intensity resistance training increases muscular size and strength when combined with resistance exercise with blood flow restriction for other muscle groups. It was suggested that any circulating factor(s) was involved in this remote effect of exercise on muscular size.

Vastus Medialis Activation during Knee Extension Exercises: Evidence for Exercise Prescription

Knee extension exercise is an important part of knee rehabilitation. Clinicians prescribe non-weight bearing exercise initially and progress patients to weight bearing exercise once they can perform a straight leg raise (SLR). Compare VM activation during a SLR and weight bearing exercises. One-way repeated measures design. University Laboratory. Fifteen healthy subjects. One SLR exercise and 6 weight-bearing knee extension exercises. Electromyographic amplitudes for the VM expressed as a percent maximum voluntary isometric contraction. The SLR had greater activation than the single leg stance and bilateral squat exercises. The step-up and unilateral leg press exercises had the greatest activation. SLR performance can be an important indicator for exercise progression. These results provide foundational knowledge to assist clinicians with exercise prescription.

Cardiac denervation does/does not play a major role in exercise limitation after heart transplantation

Cardiac denervation does/does not play a major role in exercise limitation after heart transplantation

Exercise for optimising peak bone mass in women

Physical activity is one of the major non-pharmacological methods for increasing and maintaining bone mineral density (BMD) and geometry. As such, it has an important role in maintaining peak bone mass and strength, thus reducing the risk of future osteoporotic fracture. However, not all exercise is effective, so a prescription in terms of optimal type, intensity, frequency and duration is required. Studies using animal models suggest that loading that is high in magnitude, rapidly applied and novel is most effective, whilst duration is less important beyond a threshold number of cycles. In human subjects cross-sectional studies comparing different athletic populations suggest that those who participate in high- or odd-impact sports have higher BMD; whilst impact exercise, strength training and brief high-impact-jump training interventions increase BMD in premenopausal women. In order to further elucidate exercise recommendations to optimise bone health in this population, the usefulness of brief high-impact unilateral exercises has been evaluated. Brief hopping exercises were shown to be feasible for sedentary premenopausal women, producing ground-reaction forces as high as those from jumping. Regularly performing these hopping exercises over 6 months was found to increase femoral-neck BMD of the trained leg relative to the control leg. Unilateral high-impact exercise may therefore improve bone strength of the trained limb and provide a useful model for comparing exercise prescriptions to help define the most efficient and effective exercise recommendations for the bone health of premenopausal women.

Fractional Anisotropy Values of Calf Muscles in Normative State after Exercise: Preliminary Results

We measured fractional anisotropy (FA) of calf muscles from diffusion tensor (DT) images from simultaneous scanning of bilateral calves and determined changes in values after unilateral exercise loading. We obtained DT images of both calves of 10 healthy male volunteers and measured FA of the anterior tibialis, gastrocnemius, and soleus muscles. Two of the ten were subjected to loaded exercise in their right calves; we recorded FA values immediately after exercise and 24 hours, 72 hours, and 1 week later. At rest, the mean FA values of the 20 calves were 0.63+/-0.02 in the anterior tibialis, 0.56+/-0.05 in the gastrocnemius, and 0.57+/-0.04 in the soleus muscles. The differences were statistically significant (P<0.001) by analysis of variance (ANOVA), and differences between anterior tibialis and gastrocnemius (corrected P<0.01) and anterior tibialis and soleus (corrected P<0.01) muscles were significant by Bonferroni post hoc test. The FA values of the exercise-loaded soleus and gastrocnemius muscles of the 2 volunteers decreased just after exercise but gradually recovered to the baseline after one week. Our method may be useful for assessing minimal muscle damage related to muscle fatigue.

Minimal whey protein with carbohydrate stimulates muscle protein synthesis following resistance exercise in trained young men

Whey protein is a supplemental protein source often used by athletes, particularly those aiming to gain muscle mass; however, direct evidence for its efficacy in stimulating muscle protein synthesis (MPS) is lacking. We aimed to determine the impact of consuming whey protein on skeletal muscle protein turnover in the post-exercise period. Eight healthy resistance-trained young men (age=21+/-1 .0 years; BMI=26.8+/-0.9 kg/m2 (means+/-SE)) participated in a double-blind randomized crossover trial in which they performed a unilateral leg resistance exercise workout (EX: 4 sets of knee extensions and 4 sets of leg press; 8-10 repetitions/set; 80% of maximal), such that one leg was not exercised and acted as a rested (RE) comparator. After exercise, subjects consumed either an isoenergetic whey protein plus carbohydrate beverage (WHEY: 10 g protein and 21 g fructose) or a carbohydrate-only beverage (CHO: 21 g fructose and 10 g maltodextran). Subjects received pulse-tracer injections of L-[ring-2H5]phenylalanine and L-[15N]phenylalanine to measure MPS. Exercise stimulated a rise in MPS in the WHEY-EX and CHO-EX legs, which were greater than MPS in the WHEY-RE leg and the CHO-RE leg (all p<0.05), respectively. The rate of MPS in the WHEY-EX leg was greater than in the CHO-EX leg (p<0.001). We conclude that a small dose (10 g) of whey protein with carbohydrate (21 g) can stimulate a rise in MPS after resistance exercise in trained young men that would be supportive of a positive net protein balance, which, over time, would lead to hypertrophy.

89 Cerebral and muscle oxygenation responses during unilateral and bilateral quadriceps exercise in healthy females

89 Cerebral and muscle oxygenation responses during unilateral and bilateral quadriceps exercise in healthy females