Resistance training and hormone replacement increase MMP-2 activity, quality and quantity of bone in ovariectomized rats

AIMS: The aim of the present study was to investigate the influence of resistance training (RT) and hormone replacement (HR) on MMP-2 activity, biomechanical and physical properties bone of ovariectomized (OVX) rats. METHODS: Sprague-Dawley female rats were grouped into six experimental groups (n = 11 per group): sham-operated sedentary (SHAM Sed), ovariectomized sedentary (OVX Sed), sham-operated resistance training (SHAM RT), ovariectomized resistance training (OVX RT), ovariectomized sedentary hormone replacement (OVX Sed-HR), and ovariectomized resistance training hormone replacement (OVX RT-HR). HR groups received implanted silastic capsules with a 5% solution of 17ß-estradiol (50 mg 17ß-estradiol/ml of sunflower oil). In a 12-week RT period (27 sessions; 4-9 climbs) the animals climbed a 1.1 m vertical ladder with weights attached to their tails. Biomechanical and physical bone analyses were performed using a universal testing machine, and MMP-2 activity analysis was done by zymography. RESULTS: Bone density and bone mineral content was higher in the RT and HR groups. The MMP-2 activity was higher in the RT and HR groups. The biomechanical analysis (stiffness, fracture load and maximum load) demonstrated better bone tissue quality in the RT associated with HR. CONCLUSION: The RT alone as well as when it is associated with HR was efficient in increasing MMP-2 activity, biomechanical and biophysical properties bone of ovariectomized rats.(AU)

Influência da ordem dos exercícios sobre a resposta do hormônio do crescimento e cortisol / Influence of exercise order in GH and cortisol hormonal response

O objetivo deste estudo foi investigar a resposta hormonal aguda ao treinamento de força em diferentes ordens de exercícios. Dez homens treinados (22,4 ± 2,7 anos; 80,3 ± 5,7 kg; 180 ± 8 cm; 21,5 ± 0,3 kg.m-2) participaram do estudo e completaram dois protocolos experimentais com diferentes ordenações de exercícios. As sequências foram compostas de três séries para cada exercício usando 70% de 1RM, com dois minutos de intervalo de descanso entre séries e exercícios com intervalo de sete dias entre elas. A ordem dos exercícios para SEQA foram: supino reto (SR), puxada no pulley pela frente (PF), desenvolvimento (DES), rosca direta (RD) e tríceps no pulley (TP). A ordem dos exercícios para SEQB foram TP, RD, DES, PF e SR. As variáveis sanguíneas analisados foram hormônio de crescimento (GH) e cortisol pré e imediamente pós-esforço a execução da sessão de treinamento. Os resultados demonstram que a SEQA promoveu maior e significativo aumento na concentração do GH imediatamente após a sessão, quando comparado a SEQB. A concentração de cortisol apresentou um aumento significativo quando comparado os momentos pré e pós para ambas as sequências. No entanto, não houve diferença estatisticamente significativa quando feita a comparação entre as sequências. Portanto, parece que a ordem dos exercícios pode influenciar as respostas do GH sendo que exercícios para grandes grupos musculares promovem um aumento significativo deste hormônio do que exercícios para pequenos grupos musculares no início da sessão.

The aim of this study was to investigate the acute hormonal response to resistance training sessions with different exercises order in men. Ten recreationally trained men (22.4 ± 2.7 years; 80.3 ± 5.7 kg; 180 ± 8 cm; 21.5 ± 0.3 kg.m-2) participated in the study. All subjects completed two experimental protocols with different exercises order. The exercise sequences were composed by three sets using 70%of 1RM for each exercise with 2 minutes rest between sets and exercises and separated by seven days between them. Exercise order for SEQA was bench press (BP), lat-pull down (LPD), seated shoulder press(SP), biceps curl (BC) and tríceps extension (TE). The exercises order for SEQB order were TE, BC, SP,LPD and BP. The blood variables analyzed were: growth hormone (GH), cortisol before (Pre) and immediately after (Post) each exercise session. The results shown that SEQA promoted higher and significantly increases in GH concentration immediately post session, as compared with SEQB. The cortisol concentration presented a significantly increase when compared pre and post moments for both sequences. However, there were not statistically differences when compared SEQA and SEQB post session. In conclusion, seems that exercises order can influences the GH responses, being exercises for large muscle group promoted a significantly increase in this hormone than exercises for small muscle group at the beginning of training session.