This work examined lentils as an optimal and acceptable pre-exercise meal for athletes of high intensity intermittent exercise. Thirteen male athletes participated in 4 simulated soccer trials with a repeated-measures crossover design. Along with a fasted control condition, isocaloric lentil, potato & egg white, or potato meals providing 1.5 g total carbohydrate/kg were consumed 2-h before the trials. Pre-exercise meal sensory acceptability and digestive tolerability were measured throughout testing with fixed-point scales: A sensory test meal analysis and gastrointestinal digestive symptom rating scale. Participant demographics, nutrition knowledge, and psychosocial perceptions towards lentils were assessed with a questionnaire. Distance covered on a 5 x 1 min repeated sprint test (2.5 min rest) at the end of the soccer trial assessed exercise performance. The Borg Scale (0-20) determined ratings of perceived exertion during exercise testing. Barriers toward pulse-based meal consumption negatively correlated with weekly pulse consumption (r=-0.902, p <0.05), while a positive correlation existed between beneficial beliefs of pulse-based meal consumption and weekly pulse consumption (r=0.620, p <0.05). Participants consumed an average of 79.5 ± 1.8% of each meal. The meals were perceived large in size and cumbersome to ingest by the participants, and no between meal differences were observed (p>0.05). The lentil meal was not as appealing in aroma, appearance, or flavour compared to the potato meal, but no different than the potato & egg meal (p>0.05). Lentil consumption resulted in a minimal increase in nausea compared to the other conditions (1.0, 0.54, 0.31 and 0.08, for lentil, potato & egg, potato, and control, respectively, p<0.05). Initially after consumption, all meals resulted in more bloating and fullness, and less hunger than control (p<0.05). Improved overall exercise performance was proportional with greater pre-exercise meal energy (r = 0.68, p <0.05) and carbohydrate intake (r = 0.67, p<0.05). Pre–exercise consumption of the low glycemic index lentil meal, as well as the two high glycemic pre-exercise meals, resulted in improved total sprint distances compared to the fasted control condition (p<0.05). The comparative sensory acceptability, digestive tolerability and similar performance outcomes of the lentil meal to the other pre-exercise meals indicates lentils may be a suitable pre-exercise meal for athletes of high intensity intermittent exercise.

Effects of a Short Work/Shorter Rest Intermittent Exercise on Muscle Metabolic Status, VO2, Hemoglobin Saturation and Performance, PhD, 2010, Glen Robert Belfry, Exercise Science, University of Toronto. Abstract Many sports require short duration work periods and short duration rest periods (INT). This dissertation examines the engagement of aerobic and anaerobic energy systems in acute exercise with brief (10 seconds) work and recovery (5 seconds) and the effect of chronic exposure on those systems. The differences between INT and continuous exercise (CONT) of deoxygenated hemoglobin saturation (ΔHHb), the pattern of breath-by-oxygen uptake (VO2) and muscle metabolic status, including, [Pi], [Pi]/[PCr], and [H+] were studied in young healthy adults. The physiological and performance responses to a four week, 12 session cycle ergometer training regime of the CONT and INT protocols were observed. Fluctuations in VO2, ∆HHb, [PCr], and [H+] were observed within the work : recovery duty cycle of INT. Fluctuations of VO2, ΔHHb, and [PCr] may be a function of the priming effects of previous high intensity exercise, inhibition at the locus of metabolic control, and elevated blood flow over the recovery-work transitions. Fluctuations in oxidative phosphorylation were associated with concurrent fluctuations in [PCr]. [Pi] and [PCr] were greater in INT vs CONT, whereas no differences were observed for [H+] between conditions. Reduced [PCr] may be the most appropriate indicator of metabolic stress, not increased [Pi] or [H+]. Similar improvements in aerobic power were observed for CONT and INT training, whereas anaerobic performance was enhanced post-INT training. Collectively the findings indicate that a unique INT exercise protocol facilitates increased muscle blood flow versus continuous exercise, the temporal association of muscle metabolic status, ΔHHb, and pulmonary VO2 with work rate, the apt use of [PCr] as a proxy for metabolic stress, and when this unique INT bout is utilized as a training protocol, adaptations in both aerobic and anaerobic metabolism will occur.

Effects of a Short Work/Shorter Rest Intermittent Exercise on Muscle Metabolic Status, VO2, Hemoglobin Saturation and Performance, PhD, 2010, Glen Robert Belfry, Exercise Science, University of Toronto. Abstract Many sports require short duration work periods and short duration rest periods (INT). This dissertation examines the engagement of aerobic and anaerobic energy systems in acute exercise with brief (10 seconds) work and recovery (5 seconds) and the effect of chronic exposure on those systems. The differences between INT and continuous exercise (CONT) of deoxygenated hemoglobin saturation (ΔHHb), the pattern of breath-by-oxygen uptake (VO2) and muscle metabolic status, including, [Pi], [Pi]/[PCr], and [H+] were studied in young healthy adults. The physiological and performance responses to a four week, 12 session cycle ergometer training regime of the CONT and INT protocols were observed. Fluctuations in VO2, ∆HHb, [PCr], and [H+] were observed within the work : recovery duty cycle of INT. Fluctuations of VO2, ΔHHb, and [PCr] may be a function of the priming effects of previous high intensity exercise, inhibition at the locus of metabolic control, and elevated blood flow over the recovery-work transitions. Fluctuations in oxidative phosphorylation were associated with concurrent fluctuations in [PCr]. [Pi] and [PCr] were greater in INT vs CONT, whereas no differences were observed for [H+] between conditions. Reduced [PCr] may be the most appropriate indicator of metabolic stress, not increased [Pi] or [H+]. Similar improvements in aerobic power were observed for CONT and INT training, whereas anaerobic performance was enhanced post-INT training. Collectively the findings indicate that a unique INT exercise protocol facilitates increased muscle blood flow versus continuous exercise, the temporal association of muscle metabolic status, ΔHHb, and pulmonary VO2 with work rate, the apt use of [PCr] as a proxy for metabolic stress, and when this unique INT bout is utilized as a training protocol, adaptations in both aerobic and anaerobic metabolism will occur.

In recent years our understanding of the physical demands of soccer has improved. We know that the intensity at which the game is played has increased and that the fixture schedules for professional teams can often be very congested. These factors are likely to have increased the importance placed on the physical condition of players. Therefore, the process of monitoring the fitness levels of players is likely to be an important task within clubs. Any fitness assessments that are employed need to be sensitive enough to detect changes that may result from different training stimuli. A further critical consideration for clubs is what are the best practices to implement in order to maximise recover between matches? The two areas that are central to successful recovery of performance are the restoration of muscle and liver glycogen stores and the rapid reduction of muscle soreness. We have a good understanding of the importance of carbohydrate feeding in the immediate hours following the completion of exercise, furthermore that high levels of carbohydrate consumed during short recovery periods can improve subsequent endurance running capacity in both continuous and intermittent exercise. However, there is dearth of literature investigating the effects that different types (glycemic index) of carbohydrates have on subsequent performance of high intensity intermittent exercise. Furthermore, we know that the movement patterns experienced in soccer commonly induce symptoms of muscle damage. Despite this there is little research based information on modalities that reduce these potentially detrimental side-effects (Bamett, 2006). For these reasons the series of investigations that have been conducted in this thesis were designed with the intent to examine areas that are critical to the preparation and recovery of soccer players. The first of five experimental chapters collated information on the use of fitness testing within English professional football. It was concluded that the practise of fitness testing players is extremely commonplace and that field-based testing protocols were far more popular an assessment method. The second experimental chapter went on to demonstrate that the most commonly used fitness test within professional football (MSFT) was sensitive enough to detect performance changes that occur as a result of training. A further finding within the context of the question was that it is possible for female players to significantly improve aerobic capabilities with additional high intensity aerobic training. The third experimental chapter investigated the effect different glycemic index high CHO diets could have on recovery of performance following 90 min of intermittent soccer type exercise. This study concluded that consuming either predominately high or low GI CHO mixed meals in the 24h recovery period between bouts of high intensity prolonged intermittent exercise had no difference on measures of performance. The final two experimental chapters went on to investigate the effects of cold water immersion on indices of muscle damage following intermittent exercise. Results from these investigations suggest that submerging individuals in 10°C water immediately following high intensity intermittent exercise reduces some but not all indices of muscle damage. In summary, fitness assessments of players are commonly made within professional football clubs. The most common test used was the MSFT and this appears to be sensitive to changes that result as a consequence of training. During recovery from high intensity intermittent exercise the importance of carbohydrates is apparent although the type of carbohydrate appears to be less important, furthermore, cold-water immersion may be effective in reducing some but not all indices of muscle damage.

Estudos recentes têm demonstrado que a suplementação de beta-alanina (BA) pode melhorar o desempenho físico. O mecanismo proposto para tal resultado envolve o aumento das concentrações intramusculares de carnosina, um dipeptídeo cuja função mais bem atribuída é a de manutenção do equilíbrio ácido-básico. Apesar do emergente corpo literário acerca dos efeitos ergogênicos da suplementação de BA, a maior parte das evidências provém de estudos conduzidos com indivíduos não treinados ou fisicamente ativos, enquanto os estudos com indivíduos treinados são escassos, e seus resultados, controversos. Tem sido especulado que a diferença na capacidade tamponante muscular entre indivíduos treinados e não treinados é um possível fator mascarando o efeito ergogênico da suplementação de BA em indivíduos treinados, já que têm sido demonstrado que este perfil de indivíduos possui maior capacidade tamponante e conteúdo muscular de carnosina. Assim, o objetivo do presente estudo foi investigar a influência do estado de treinamento sobre o desempenho físico intermitente de membros inferiores em resposta à suplementação de BA. Para tanto, 40 homens jovens e saudáveis foram recrutados para participar do estudo, e divididos em dois grupos de acordo com o seu estado de treinamento [ciclistas treinados (T) ou indivíduos não treinados (NT)]. Os participantes foram aleatoriamente designados a um grupo suplementado com BA ou placebo (dextrose - PL), provendo quatro condições experimentais: NTPL, NTBA, TPL e TBA. A suplementação foi realizada com a ingestão de 6.4 gramas de BA ou PL por dia, durante 4 semanas. Antes e após o período de suplementação, os participantes completaram 4 séries do teste de Wingate para membro inferior, com 30 segundos de duração cada uma e 3 minutos de descanso entre elas. O trabalho total realizado foi significantemente aumentado após o período de suplementação em ambos os grupos NTBA (+1349 ± 1411 kJ; P = 0.03) e TBA (+1978 ± 1508 kJ; P = 0.002), foi significantemente reduzido no grupo NTPL (-1385 ± 2815 kJ; P = 0.03), e não se alterou no grupo TPL (-219 ± 1507 kJ; P = 0.73). Comparada ao período pré-suplementação, a potência média no período pós-suplementação foi significantemente maior na série 4 para o grupo NTBA (P = 0.0004), enquanto a mesma foi maior nas séries 1, 2 e 4 (P <= 0.05) para o grupo TBA. Não foram observadas diferenças na potência média entre o período pré- e pós-suplementação para os grupos NTPL e TPL. Em conclusão, quatro semanas de suplementação de BA foram efetivas em melhorar o desempenho físico intermitente de membros inferiores em ambos os participantes treinados e não treinados. Estes dados ressaltam a eficácia ergogênica da suplementação de BA para exercícios de alta-intensidade, independentemente do estado de treinamento do indivíduo / Recent studies have demonstrated that beta-alanine (BA) supplementation can improve performance. The proposed mechanisms for this result involve an increased muscle carnosine content, a dipeptide whose function is attributed to the maintenance of acid-base balance. Even though the body of evidence surrounding the ergogenic effects of BA supplementation is increasing, most of the evidences come from studies conducted with physically active or untrained individuals, while studies with trained participants are scarce, and their results, controversial. It has been speculated that the difference in muscle buffering capacity between trained and untrained individuals is a possible factor masking the ergogenic effect of BA supplementation in trained individuals, who have already been demonstrated to have greater buffering capacity and muscle carnosine content. Therefore, the aim of this study was to investigate the influence of training status on intermittent lower-body performance in response to BA supplementation. For this purpose, forty young males were divided into two groups according to their training status (trained - T, and untrained - NT cyclists). Participants were further randomly allocated to BA or placebo (dextrose - PL) groups, providing four experimental conditions: NTPL, NTBA, TPL, TBA. BA or PL was ingested by 6.4 g·d-1, during for 4 weeks. Before and after the supplementation period, participants completed four 30-seconds lower-body Wingate bouts, separated by 3 minutes. Total work done was significantly increased following supplementation in both NTBA (+1349 ± 1411 kJ; P = 0.03) and TBA (+1978 ± 1508 kJ; P = 0.002), and it was significantly reduced in NTPL (-1385 ± 2815 kJ; P = 0.03) with no difference for TPL (-219 ± 1507 kJ; P = 0.73). Compared to pre-supplementation, post-supplementation mean power output was significantly higher in bout 4 for NTBA (P = 0.0004), and higher in bouts 1, 2 and 4 (P <= 0.05) for TBA. No differences were observed in mean power output for NTPL and TPL from pre- to post-supplementation period. In conclusion, four weeks of BA supplementation was effective at improving intermittent lower-body performance in both untrained and trained individuals. These data highlight the efficacy of BA as an ergogenic aid for high-intensity exercise regardless of the training status of the individual

Submitted by Anelise Milech (anelisemilech@gmail.com) on 2017-11-09T12:03:46Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Marcelo dos Santos Vaz.pdf: 953963 bytes, checksum: b15cb5f0a33aaed7f35abb2dbbbaa69d (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-01-02T13:49:36Z (GMT) No. of bitstreams: 2 Marcelo dos Santos Vaz.pdf: 953963 bytes, checksum: b15cb5f0a33aaed7f35abb2dbbbaa69d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-01-02T13:50:34Z (GMT) No. of bitstreams: 2 Marcelo dos Santos Vaz.pdf: 953963 bytes, checksum: b15cb5f0a33aaed7f35abb2dbbbaa69d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-01-02T13:50:43Z (GMT). No. of bitstreams: 2 Marcelo dos Santos Vaz.pdf: 953963 bytes, checksum: b15cb5f0a33aaed7f35abb2dbbbaa69d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-07-20 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Impacto fisiológico de sessões de treinamento com remoergômetro. Vinte sujeitos (7 remadores amadores e 13 universitários) remaram três sessões de treino equiparadas pela duração total (40 min): uma ontínua (EC = 60% VO2max), uma intermitente com esforços curtos (RST = 9 x 30” [150% VO2max] / 4’ [40% VO2max]) e uma intermitente com esforços longos (IL = 8 x 2’ [80% VO2max] / 3’ [40% VO2max]. oletaram-se VO2 antes, durante e após o esforço, concentração de lactato [Lac], creatina quinase ([CK]), frequência cardíaca (FC) e parâmetros da variabilidade da frequência cardíaca (VFC): LH/HF e RMSSD pré-, pós- e pós 24h do treino. Foi encontrada diferença entre grupos, com maior contribuição aeróbia no EC em comparação às sessões intermitentes (p<0,001). Para [Lac], o pós-treino do IL foi maior que o do EC (p=0,004). A VFC foi diferente entre momentos, com maior valor nos pós-treinos, em relação aos pré- e pós 24h (p<0,001). Já a [CK] seguiu comportamento linear com aumento significativa no pós-treino e no pós 24h (p<0,001). Conclui-se que as sessões de treinamento resultaram em contribuição similar dos sistemas energéticos, com predominância aeróbia expressiva e ligeiramente mais pronunciada no EC, em comparação a RST e IL. Portanto, o emprego de treinos contínuos e intermitentes é viável ao se considerar 24 horas de intervalo entre sessões, tempo suficiente para a recuperação dos remadores, independente do tempo de prática dos sujeitos e do tipo de estímulo aplicado. / The objective of the study was to measure the contribution of energy systems and characterize Physiological impact of training sessions with ergometer. Twenty subjects (7 rowers amateurs and 13 university students) had three training sessions matched for the total duration (40 min): one continuous (EC = 60% VO2max), one intermittent with short stresses (RST = 9 x 30% [150% VO2max] / 4 '[40% VO2max]) and an intermittent with long efforts (IL = 8 x 2' [80% VO2max] / 3 '[40% VO2max]. VO2 was collected before, during and after exercise, concentration of lactate [Lac], creatine kinase ([CK]), heart rate (HR) and parameters of variability of heart rate (HRV): LH / HF and RMSSD pre-, post- and post-training 24 hours. It found difference between groups, with higher aerobic contribution in the CS compared to the (p <0.001). For [Lac], posttraining of IL was greater than that of EC (p = 0.004). The VFC was different between moments, with a higher value in the post-training, in relation to pre and post 24h (p <0.001). On the other hand, [CK] followed a linear behavior with a significant increase in post- after 24 h (p <0.001). It is concluded that the training sessions resulted in a energy systems, with expressive aerobic predominance and EC, compared to RST and IL. Therefore, the use of continuous and intermittent is feasible when considering 24 hours interval between sessions, sufficient time for the recovery of rowers, regardless of the subjects' practice time and the type of stimulus applied.

abstract: Purpose: The purpose of this study was to examine the acute effects of two novel intermittent exercise prescriptions on glucose regulation and ambulatory blood pressure. Methods: Ten subjects (5 men and 5 women, ages 31.5 &plusmn; 5.42 yr, height 170.38 &plusmn; 9.69 cm and weight 88.59 &plusmn; 18.91 kg) participated in this four-treatment crossover trial. All subjects participated in four trials, each taking place over three days. On the evening of the first day, subjects were fitted with a continuous glucose monitor (CGM). On the second day, subjects were fitted with an ambulatory blood pressure monitor (ABP) and underwent one of the following four conditions in a randomized order: 1) 30-min: 30 minutes of continuous exercise at 60 - 70% VO2peak; 2) Mod 2-min: twenty-one 2-min bouts of walking at 3 mph performed once every 20 minutes; 3) HI 2-min: eight 2-min bouts of walking at maximal incline performed once every hour; 4) Control: a no exercise control condition. On the morning of the third day, the CGM and ABP devices were removed. All meals were standardized during the study visits. Linear mixed models were used to compare mean differences in glucose and blood pressure regulation between the four trials. Results: Glucose concentrations were significantly lower following the 30-min (91.1 &plusmn; 14.9 mg/dl), Mod 2-min (93.7 &plusmn; 19.8 mg/dl) and HI 2-min (96.1 &plusmn; 16.4 mg/dl) trials as compared to the Control (101.1 &plusmn; 20 mg/dl) (P < 0.001 for all three comparisons). The 30-min trial was superior to the Mod 2-min, which was superior to the HI 2-min trial in lowering blood glucose levels (P < 0.001 and P = 0.003 respectively). Only the 30-min trial was effective in lowering systolic ABP (124 &plusmn; 12 mmHg) as compared to the Control trial (127 &plusmn; 14 mmHg; P < 0.001) for up to 11 hours post exercise. Conclusion: Performing frequent short (i.e., 2 minutes) bouts of moderate or high intensity exercise may be a viable alternative to traditional continuous exercise in improving glucose regulation. However, 2-min bouts of exercise are not effective in reducing ambulatory blood pressure in healthy adults. / Dissertation/Thesis / Ph.D. Physical Activity, Nutrition and Wellness 2013

Female soccer is becoming more popular and professional in the world. There are, however, limited scientific data available on how elite female players respond to physical stress during soccer games. An effective recovery strategy following a game is important, because there are few recovery days between the games in international tournaments. The present thesis, which was designed to mirror a competitive situation, aimed to investigate changes in several physiological systems occurring in female elite players in response to two soccer games. It also aimed to investigate the effects of active recovery training on the recovery of several physiological systems. METHODS: Two elite female soccer teams played two 90-min games separated by 72 h active or passive recovery. The active recovery training (cycling at 60% HRpeak, resistance training at &lt;50% 1RM) lasted one hour and was performed 22 and 46 h after the first game. Countermovement jump (CMJ), 20-m sprint time and isokinetic knee strength were measured before, immediately, 5, 21, 45, 51, and 69 h after the first game, and immediately after the second game. The physical stress markers (CK, urea), oxidative stress markers (e.g., GSSG, lipid peroxidation), endogenous (e.g., UA, thiols) and dietary antioxidants (e.g., tocopherols, carotenoids) and a large battery of cytokines (e.g., IL-6, TNF-α) were analysed in blood. RESULTS: No significant differences were observed in the performance parameters, oxidative stress and antioxidant levels or inflammatory response between the active and passive recovery groups. Sprint and isokinetic knee strength were reduced by the same extent after both games. CMJ decreased after the first game and remained reduced throughout the study period. Blood physical stress markers, GSSG and endogenous antioxidants increased with similar amplitude after both games together with unchanged lipid peroxidation. The dietary antioxidants showed either a rapid and persistent change (e.g., tocopherols) or a delayed rise (carotenoids) after the first game. A transient increase occurred in several pro- (e.g., IL-12, TNF-a, MCP-1), anti-inflammatory (e.g., IL-4, IL-10, INF-a) and mixed (IL-6) cytokines after the first game. Fewer cytokines increased in response to the second game. CONCLUSION: Two repeated elite female soccer games separated by 72 h induced similar acute changes in several physiological parameters. After the first game, differences in the recovery pattern of the neuromuscular parameters occurred. In particular, the slow recovery of CMJ indicates that special attention should be devoted to the training of explosive force. Furthermore, the recruitment of antioxidants in response to the transient increase in GSSG resulted in the maintenance of the redox-balance in female players. Similarly, a strong and balanced pro- and anti-inflammatory cytokine response occurred after one single female soccer game. The consequences of the dampened cytokine response during repeated soccer games are, however, unknown. In general, the majority of the parameters had recovered prior to the second game and the physiological alterations induced by the first game did not affect the performance of players in the second game. Finally, active recovery training conducted after a soccer game does not accelerate the recovery time for neuromuscular, oxidative stress, antioxidant and inflammatory responses in elite female players.

Estudos recentes têm demonstrado que a suplementação de beta-alanina (BA) pode melhorar o desempenho físico. O mecanismo proposto para tal resultado envolve o aumento das concentrações intramusculares de carnosina, um dipeptídeo cuja função mais bem atribuída é a de manutenção do equilíbrio ácido-básico. Apesar do emergente corpo literário acerca dos efeitos ergogênicos da suplementação de BA, a maior parte das evidências provém de estudos conduzidos com indivíduos não treinados ou fisicamente ativos, enquanto os estudos com indivíduos treinados são escassos, e seus resultados, controversos. Tem sido especulado que a diferença na capacidade tamponante muscular entre indivíduos treinados e não treinados é um possível fator mascarando o efeito ergogênico da suplementação de BA em indivíduos treinados, já que têm sido demonstrado que este perfil de indivíduos possui maior capacidade tamponante e conteúdo muscular de carnosina. Assim, o objetivo do presente estudo foi investigar a influência do estado de treinamento sobre o desempenho físico intermitente de membros inferiores em resposta à suplementação de BA. Para tanto, 40 homens jovens e saudáveis foram recrutados para participar do estudo, e divididos em dois grupos de acordo com o seu estado de treinamento [ciclistas treinados (T) ou indivíduos não treinados (NT)]. Os participantes foram aleatoriamente designados a um grupo suplementado com BA ou placebo (dextrose - PL), provendo quatro condições experimentais: NTPL, NTBA, TPL e TBA. A suplementação foi realizada com a ingestão de 6.4 gramas de BA ou PL por dia, durante 4 semanas. Antes e após o período de suplementação, os participantes completaram 4 séries do teste de Wingate para membro inferior, com 30 segundos de duração cada uma e 3 minutos de descanso entre elas. O trabalho total realizado foi significantemente aumentado após o período de suplementação em ambos os grupos NTBA (+1349 ± 1411 kJ; P = 0.03) e TBA (+1978 ± 1508 kJ; P = 0.002), foi significantemente reduzido no grupo NTPL (-1385 ± 2815 kJ; P = 0.03), e não se alterou no grupo TPL (-219 ± 1507 kJ; P = 0.73). Comparada ao período pré-suplementação, a potência média no período pós-suplementação foi significantemente maior na série 4 para o grupo NTBA (P = 0.0004), enquanto a mesma foi maior nas séries 1, 2 e 4 (P <= 0.05) para o grupo TBA. Não foram observadas diferenças na potência média entre o período pré- e pós-suplementação para os grupos NTPL e TPL. Em conclusão, quatro semanas de suplementação de BA foram efetivas em melhorar o desempenho físico intermitente de membros inferiores em ambos os participantes treinados e não treinados. Estes dados ressaltam a eficácia ergogênica da suplementação de BA para exercícios de alta-intensidade, independentemente do estado de treinamento do indivíduo / Recent studies have demonstrated that beta-alanine (BA) supplementation can improve performance. The proposed mechanisms for this result involve an increased muscle carnosine content, a dipeptide whose function is attributed to the maintenance of acid-base balance. Even though the body of evidence surrounding the ergogenic effects of BA supplementation is increasing, most of the evidences come from studies conducted with physically active or untrained individuals, while studies with trained participants are scarce, and their results, controversial. It has been speculated that the difference in muscle buffering capacity between trained and untrained individuals is a possible factor masking the ergogenic effect of BA supplementation in trained individuals, who have already been demonstrated to have greater buffering capacity and muscle carnosine content. Therefore, the aim of this study was to investigate the influence of training status on intermittent lower-body performance in response to BA supplementation. For this purpose, forty young males were divided into two groups according to their training status (trained - T, and untrained - NT cyclists). Participants were further randomly allocated to BA or placebo (dextrose - PL) groups, providing four experimental conditions: NTPL, NTBA, TPL, TBA. BA or PL was ingested by 6.4 g·d-1, during for 4 weeks. Before and after the supplementation period, participants completed four 30-seconds lower-body Wingate bouts, separated by 3 minutes. Total work done was significantly increased following supplementation in both NTBA (+1349 ± 1411 kJ; P = 0.03) and TBA (+1978 ± 1508 kJ; P = 0.002), and it was significantly reduced in NTPL (-1385 ± 2815 kJ; P = 0.03) with no difference for TPL (-219 ± 1507 kJ; P = 0.73). Compared to pre-supplementation, post-supplementation mean power output was significantly higher in bout 4 for NTBA (P = 0.0004), and higher in bouts 1, 2 and 4 (P <= 0.05) for TBA. No differences were observed in mean power output for NTPL and TPL from pre- to post-supplementation period. In conclusion, four weeks of BA supplementation was effective at improving intermittent lower-body performance in both untrained and trained individuals. These data highlight the efficacy of BA as an ergogenic aid for high-intensity exercise regardless of the training status of the individual

Recent years have witnessed significant research into the acute effects of exercise on appetite, energy intake and gut hormone responses. The experiments in this thesis have further investigated this topic by examining the appetite, acylated ghrelin, peptide YY and energy intake responses to energy deficits induced via different exercise protocols and food restriction. To achieve this, 48 young healthy males (mean (SD): age 23 (3) years, body mass index 23.7 (2.7) kg.m-2, maximum oxygen uptake 52.9 (9.8) mL.kg 1.min-1) were recruited into four studies. In study one, 60 min of treadmill running at 70% of VO2 max did not stimulate any increases in appetite or daily energy intake regardless of whether the exercise was performed after breakfast or in the fasted state. In study two, six 30 s Wingate tests stimulated increases in appetite during the subsequent hours compared with 60 min of cycling at 68% of VO2 max. Differences in appetite appeared to be unrelated to changes in plasma acylated ghrelin concentrations and did not influence ad libitum energy intake. Subsequently, endurance exercise resulted in a significantly greater negative daily energy balance than sprint exercise due to a larger exercise energy expenditure. Study three revealed that appetite and energy intake did not differ from a resting control trial after either ten, 4 min cycling bouts at 85 90% of VO2 max separated by 2 min of rest or 60 min of constant cycling at 60% of VO2 max. This occurred despite elevated PYY3-36 concentrations during the hours after exercise. Finally, study four showed that an energy deficit of ~1475 kJ stimulated increases in appetite when induced via food restriction but not when achieved by an acute bout of exercise. This was associated with differences in plasma PYY3-36 concentrations but did not appear to be related to changes in circulating levels of acylated ghrelin and did not influence energy intake. This thesis has shown that appetite perceptions do not differ from a resting control trial during the hours after continuous endurance exercise. Alternatively, supramaximal cycling exercise and subtle reductions in food intake stimulated increases in appetite during the subsequent hours. Such increases in appetite do not appear to be related to changes in acylated ghrelin but may be influenced by plasma PYY3-36 concentrations. Despite differences in appetite, daily energy intake was unaffected by all interventions.