Texto para as questões 66 e 67
Researchers investigated the quantities of thousands of muscle proteins and found a possible new explanation for muscle memory. A study showed for the first time that muscles “remember” training at the protein level. It is often thought that the effects of exercise are short-lived, and a break from the gym can cause stress over muscle loss. However, the research has shown that this stress is partly unnecessary, as the effects of resistance training persist in muscles for up to two months and the gains are fast when training is started again. But what mechanisms and changes at the cellular and molecular levels explain muscle memory? In the study, ten weeks of resistance training was followed by a break of the same length and then followed by another ten weeks of resistance training. Using the proteomics method, it was possible to study the quantities of over 3,000 muscle proteins using advanced mass spectrometry equipment. The study found two types of change profiles in muscle proteins. Some proteins changed as a result of training, returned to their pre-training state during the break, and changed again during the new training period similarly to the first training period. These included proteins related to aerobic metabolism. Another group of proteins changed as a result of training and remained changed during the break and after the new training period. Among these proteins were several calcium-binding proteins, such as calpain-2, whose gene has recently been identified to retain a memory trace even after a training break. “At the level of the number of muscle nuclei and the memory traces of genes, that is, epigenetics, long-term responses that persist even after a break and possibly explain ‘muscle memory’ have previously been observed,” says a researcher. “Now, for the first time, we have shown that muscles ‘remember’ previous resistance training at the protein level for at least two and a half months.”
Disponível em https://jyu.fi/en/news/. 14 April 2025. Adaptado.
Segundo o texto, os experimentos demonstram que
a prática de esportes ativa genes através da mudança do código genético.
as quantidades de proteínas musculares apresentam mudanças após a atividade física.
a epigenética refuta a hipótese da ação da memória muscular após treinos leves.
as proteínas relacionadas ao metabolismo aeróbico ativam mudanças irreversíveis.
os métodos da proteômica dificultam a caracterização das proteínas e suas interações.
Resolução
A resposta está correta porque os pesquisadores observaram mudanças nas quantidades de proteínas musculares em resposta ao treinamento físico. O início do texto informa: “Researchers investigated the quantities of thousands of muscle proteins”, isto é, “Pesquisadores investigaram as quantidades de milhares de proteínas musculares”. O estudo acompanhou dez semanas de treinamento, dez semanas de pausa e mais dez semanas de treinamento.
Foram identificados dois padrões de mudança. No primeiro, algumas proteínas se alteraram com o treino, voltaram ao estado anterior durante a pausa e se modificaram novamente quando o treinamento foi retomado. É o que diz o trecho: “Some proteins changed as a result of training, returned to their pre-training state during the break, and changed again during the new training period”.
No segundo padrão, outras proteínas se alteraram com o treinamento e permaneceram alteradas mesmo durante a pausa e após a retomada: “Another group of proteins changed as a result of training and remained changed during the break and after the new training period”. A permanência dessas alterações é apresentada como uma possível explicação para a memória muscular: os músculos conservam efeitos do treinamento anterior no nível das proteínas.