Detraining Group Research Articles

The effect of a period of detraining followed by resistance training on fibrosis, angiogenesis, and cardiac dimensions of male Wistar rats

Background and aims: Resistance training is associated with certain cardiovascular adaptations. However, a lack of exercise may affect it. Thus, the aim of this study was to investigate the effect of a period of detraining followed by resistance training on the fibrosis, angiogenesis, and cardiac dimensions of male Wistar rats. Methods: In this experimental study, 20 male Wistar rats at the age of five weeks were randomly divided into control, training, control+detraining, and training+detraining groups. The control (8 weeks) and control+detraining (11 weeks) groups were placed in their respective cages with 24-hour free access to food and water and did not exercise for eight weeks. The resistance training+detraining and resistance training groups performed eight weeks of the resistance training protocol. The resistance training+detraining group did not do any type of training after the training period of 3 weeks. The results were analyzed by SPSS version 18. Results: In terms of fibrosis, there was a significant difference between the control and control+detraining groups (P=0.001), between control and training groups (P=0.001), and between control+detraining and training+detraining groups (P=0.001). In addition, a significant difference was found between the training and training+detraining groups in terms of fibrosis (P=0.001). In terms of angiogenesis, a significant difference was observed between the control and training groups (P=0.001) and between the training and training+detraining groups (P=0.007). Conclusion: Resistance training could reduce fibrosis and increase cardiac angiogenesis in rats. Based on the findings, fibrosis increased significantly in the detraining period compared to the active period, and angiogenesis was also reduced due to detraining.

Long-term detraining reverses the improvement of lifelong exercise on skeletal muscle ferroptosis and inflammation in aging rats: fiber-type dependence of the Keap1/Nrf2 pathway.

We investigated the effects of lifelong aerobic exercise and 8months of detraining after 10months of aerobic training on circulation, skeletal muscle oxidative stress, and inflammation in aging rats. Sprague-Dawley rats were randomly assigned to the control (CON), detraining (DET), and lifelong aerobic training (LAT) groups. The DET and LAT groups began aerobic treadmill exercise at the age of 8months and stopped training at the 18th and 26th month, respectively; all rats were sacrificed when aged 26months. Compared with CON, LAT remarkably decreased serum and aged skeletal muscle 4-hydroxynonenal (4-HNE) and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels. Superoxide dismutase 2(SOD2) levels were higher in the LAT group than in the CON group in skeletal muscle. However, DET remarkably decreased SOD2 protein expression and content in the skeletal muscle and increased malondialdehyde (MDA) level compared with LAT. Compared with LAT, DET remarkably downregulated adiponectin and upregulated tumor necrosis factor alpha (TNF-α) expression, while phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and 70-kDa ribosomal protein S6 kinase (P70S6K) protein expression decreased, and that of FoxO1 and muscle atrophy F-box (MAFbX) proteins increased in the quadriceps femoris. Adiponectin and TNF-α expression in the soleus muscle did not change between groups, whereas that of AKT, mammalian target of rapamycin (mTOR), and P70S6K was lower in the soleus in the DET group than in that in the LAT group. Compared with that in the LAT group, sestrin1 (SES1) and nuclear factor erythroid 2-related factor 2 (Nrf2) protein expression in the DET group was lower, whereas Keap1 mRNA expression was remarkably upregulated in the quadriceps femoris. Interestingly, the protein and mRNA levels of SES1, Nrf2, and Keap1 in soleus muscle did not differ between groups. LAT remarkably upregulated ferritin heavy polypeptide 1(FTH), glutathione peroxidase 4(GPX4), and solute carrier family 7member 11 (SLC7A11) protein expression in the quadriceps femoris and soleus muscles, compared with CON. However, compared with LAT, DET downregulated FTH, GPX4, and SLC7A11 protein expression in the quadriceps femoris and soleus muscles. Long-term detraining during the aging phase reverses the improvement effect of lifelong exercise on oxidative stress, inflammation, ferroptosis, and muscle atrophy in aging skeletal muscle. The quadriceps femoris is more evident than the soleus, which may be related to the different changes in the Keap1/Nrf2 pathway in different skeletal muscles.

Effects of early exercise intervention and exercise cessation on neuronal loss and neuroinflammation in a senescence-accelerated mouse prone 8

Physical exercise is beneficial for preventing Alzheimer's disease (AD) and cognitive decline through several mechanisms, including suppression of neuroinflammation and neuronal loss in the hippocampus. Despite these exercise-induced benefits in AD pathology, less attention has been paid to the importance of maintaining exercise and the consequences of detraining. This study aimed to investigate the effects of early exercise intervention and detraining on age-related cognitive decline and its protective mechanisms using senescence-accelerated mouse prone 8 (SAMP8). These mice were divided to four groups: no-exercise (No-Ex, n = 9), 4 months (4 M)-detraining (n = 11), 2 months (2 M)-detraining (n = 11), and long-term exercise (LT-Ex, n = 13). Age-related cognitive decline was prevented in the LT-Ex group compared with the No-Ex group through the suppression of neuronal loss, enhanced brain-derived neurotrophic factor (BDNF), and inhibition of neuroinflammation corresponding to reduced M1 and increased M2 microglia in the hippocampus. No significant differences were observed in cognitive function between the detraining and No-Ex groups. However, the 2 M−detraining group showed increased BDNF positive area in the CA1 region and the enhancement of anti-inflammatory M2 phenotype microglia. In contrast, no statistically beneficial exercise-induced changes in the hippocampus were observed in the 4 M−detrainig group. These results showed that early exercise intervention prevented age-related cognitive deficits in AD progression by suppressing neuronal loss and neuroinflammation in the hippocampus. Exercise-induced benefits, including the anti-inflammation in the hippocampus, may be retained after exercise cessation, even if exercise-induced beneficial effects decline in a time-dependent manner.

Effect of Detraining and Tapering Strategies on the Strength Performance of Adolescent Taekwondo Athletes

<p>目的 :分析跆拳道青少年選手完成 12週阻力訓練後，執行停訓 (detraining, DT) 或減量訓練 (tapering, TP)對力量表現之影響。方法 : 22名完成 12週阻力訓練之現役男性青少年跆拳道選手為受試者，以最大肌力水準分層隨機分配為 11位停訓組 (detraining group. DTG) 及 11位減量組 (tapering group, TPG)。TPG維持前一期訓練計畫中「速度與爆發力訓練期」之訓練強度與頻率，但訓練量減半的阻力訓練。前一期阻力訓練結束 48小時進行前測，前測結束後第 7天及第 14天分別進行中測與後測。依變項包括最大肌力、50毫秒發力率、100毫秒發力率及反向跳高度。以單因子相依變異數分析及獨立樣本t檢定比較組內與組間差異，組內差異若達顯著水準以 Bonferroni 法進行事後比較。結果 : DTG 中測與後測之最大肌力顯著優於前測 (p < .01)，中測之50毫秒發力率顯著優於前測 (p < .05)。TPG中測的最大肌力、50毫秒發力率、100毫秒發力率及反向跳高度顯著優於前測 (p < .01)，後測的50毫秒發力率亦優於前測及中測 (p < .01)。組間比較發現 DTG 中測的最大肌力進步率顯著優於TPG(p < .01)，但 TPG 後測的 50毫秒發力率進步率顯著優於 DTG (p < .01)。結論 : 7天與14天的DT與TP均能維持前一期阻力訓練之成果。7天 TP 比7天的 DT有更多力量發展的優勢且 14天TP的 50毫秒發力率達最高進步率。故TP策略比DT策略更有利跆拳道選手專項所需的力量表現。</p> <p> </p><p>Purpose: The study was to analyze the effect of detraining (DT) and tapering (TP) after 12-week resistant training on the strength performance of adolescent taekwondo athletes. Methods: 22 active male teenage taekwondo athletes who completed 12 weeks of resistance training were selected as subjects, and were randomly assigned to 11 detraining group (DTG) and 11 tapering group. TPG maintains the training intensity and frequency of the "speed and explosive power training period" in the previous training plan, but the training volume was halved. The pre-test was conducted 48 hours after the end of the previous resistance training cycle, and the mid-test and post-test were conducted on the 7th and 14th days after the pre-test. The dependent variables included maximal strength, 50-ms rate of force development (RFD), 100-ms RFD, and the height of countermovement jump. Repeated measured ANOVA and independent sample t-test were used to compare the differences within and between groups. Bonferroni’s method was used for post-hoc comparison if the differences within groups reached a significant level. Results: In DTG, the maximal strength at the mid-test and post-test was significantly greater than that of the pre-test (p< .01), and the 50-ms RFD at the mid-test was significantly better than that of the pre-test (p < .05). In TPG, the maximal strength, 50-ms RFD, 100-ms RFD, and the height of countermovement jump of the post-test were significantly better than those in the pre-test (p< .01), and the 50-ms RFD was significantly greater than the pre-test and mid-test. Between-group comparisons found that DTG was significantly better than TPG in the improvement of maximal strength (p < .01), but the 50-ms RFD at TPG post-test was significantly better than DTG post-test (p < .01). Conclusions: Both 7-day and 14-day DT and TP can maintain the training effect of pervious resistant training program. The 7-day TP could develop more strength than the 7-day DT, and the 50-ms RFD improved the most in 14-day TP. Therefore, the TP strategy is more beneficial to the strength performance required by taekwondo athletes than the DT strategy.</p> <p> </p>

Impact of Tailored Multicomponent Exercise for Preventing Weakness and Falls on Nursing Home Residents' Functional Capacity.

We aimed to determine whether the benefits of long (24weeks) and short (4weeks) training programs persisted after short (6weeks) and long (14weeks) periods of inactivity in older adult nursing home residents with sarcopenia. Multicenter randomized trial. The Vivifrail tailored, multicomponent exercise program (http://vivifrail.com) was conducted to individually prescribe exercise for frail older adults, depending on their functional capacity. The training included 4 levels combining strength and power, balance, flexibility, and cardiovascular endurance exercises. Twenty-four institutionalized older adults (87.1 ± 7.1years, 58.3% women) diagnosed with sarcopenia were allocated into 2 groups: the Long Training-Short Detraining (LT-SD) group completed 24weeks of supervised Vivifrail training followed by 6weeks of detraining; the Short Training-Long Detraining (ST-LD) group completed 4weeks of training and 14weeks of detraining. Changes in functional capacity and strength were evaluated at baseline, and after short and long training and detraining periods. Benefits after short and long exercise interventions persisted when compared with baseline. Vivifrail training was highly effective in the short term (4weeks) in increasing functional and strength performance (effect size= 0.32-1.44, P < .044) with the exception of handgrip strength. Continued training during 24weeks produced 10% to 20% additional improvements (P < .036). Frailty status was reversed in 36% of participants, with 59% achieving high self-autonomy. Detraining resulted in a 10% to 25% loss of strength and functional capacity even after 24weeks of training (effects size= 0.24-0.92, P < .039). Intermittent strategies such as 4weeks of supervised exercise 3 times yearly with no more than 14weeks of inactivity between exercise periods appears as an efficient solution to the global challenge of maintaining functional capacity and can even reverse frailty in vulnerable institutionalized older adults.

A Preliminary Study of Pre-Season Taekwondo Preparation Strategy: Personal Isolation Training Effect for Elite Athletes.

Background: The global coronavirus disease pandemic (COVID-19) has had a considerable impact on athletic competition and team sports training. Athletes have been forced to train alone at home. However, the isolation training model effects are still unknown. Purpose: This study compared the effects of personal isolation training (PIT) and detraining (DT) on specific sport performances (flexibility, power, reaction time, acceleration, and aerobic capacity) and body composition in elite taekwondo athletes. Methods: Eleven elite taekwondo athletes were recruited as voluntary subjects. Athletes were randomly paired by weight into the personal isolation training group (PIT group: N = 5, age: 21.2 ± 0.4 years, BMI: 22.2 ± 0.8 kg/m2) or detraining group (DT group: N = 6, age: 19.8 ± 0.3 years, BMI: 23.1 ± 1.0 kg/m2). All subjects performed the same training content prior to the pre-test (T1). When the pre-test was completed, all subjects underwent 12 weeks of PIT or DT. Athletes were then administrated the post-test (T2). The athlete’s sport performances and body composition were measured to compare the differences between the two groups (PIT and DT) and two phases (T1 and T2). Results: There were no significant differences in kicking reaction time and flexibility in both groups (p > 0.05). The PIT showed significant improvements in 10 m (10M) sprint performance (p < 0.05), and displayed a progress trend in Abalakov jump performance. In addition, the PIT resulted in a better change response in 10M sprint performance (PIT: −4.2%, DT: +2.1%), aerobic endurance performance (PIT: −10.2%, DT: −18.4%), right arm muscle mass (PIT: +2.9%, DT: −3.8%), and trunk muscle mass (PIT: +2.2%, DT: −1.9%) than DT (p < 0.05). The fat mass percentage showed a negative change from T1 to T2 in both groups (p < 0.05). Conclusions: PIT showed a trend toward better body composition (arm and trunk muscle) and sport performances (10M sprint and aerobic capacity) compared to DT. This finding may provide information on the effectiveness of a personal isolation training model for optimal preparation for taekwondo athletes and coaches. It may also serve as a useful and safe guideline for training recommendations during the coronavirus disease (COVID-19).

Importance of physical detraining in functional capacity of individuals with chronic peripheral arterial occlusive disease: a cross-sectional pilot study.

BackgroundPhysical training is a well-established strategy for rehabilitation of the functional capacity of individuals with chronic peripheral arterial occlusive disease (PAOD). However, some individuals quit training after participating in a physical training program, undergoing detraining. There is scant literature on the effects of physical detraining in individuals with PAOD and it is therefore important to investigate the effects of this phenomenon.ObjectivesThe objective of this article was to evaluate the effects of physical detraining on functional capacity in individuals with PAOD.MethodsCross-sectional study with 22 individuals. Participants were divided into two groups: a detraining group (DG) and a control group (CG). The distance covered in the 6-minute walk test (6MWTD) and the pain-free walking distance (PFWD) were evaluated. The PFWD is the distance covered until claudication begins, i.e., the distance covered without pain.ResultsMean age was 66 ± 8 in the DG and 67 ± 7 in the CG. There were no differences between the groups in either the 6MWTD or the PFWD (p = 0.428; p = 0.537, respectively).ConclusionsThe present pilot study allows us to conclude that the functional capacity of individuals with PAOD who participated in a physical training program and subsequently underwent detraining was not superior in relation to individuals who did not participate in a physical training program. The results of the present study serve to encourage maintenance of physical exercise, since physical training is no longer effective if detraining occurs.

Effects of long-term aerobic training and detraining on functional capacity and quality of life in hemodialysis patients: A pilot study.

Although previous studies have shown the benefits of exercise training in hemodialysis patients, little is known about the effects of long-term of exercise program on these patients. We investigated the effects and the safety of long-term aerobic training and the effects of detraining on functional capacity and quality of life in hemodialysis patients. Ten patients were allocated to two groups: training and detraining. The training group completed at least 30 months of aerobic training, and the detraining group completed at least 20 months and then discontinued the training for at least 10 months. The outcomes were analyzed at baseline, after 3 months of aerobic training and at the 30-month follow-up. The training and detraining groups performed 37 (5.5) and 24 (3.0) months of aerobic training, respectively. The detraining group discontinued the training for 11.0 (2.0) months. After 3 months of aerobic training, six-minute walking test distance increased significantly in both groups (training group = 569 (287.8) vs 635.5 (277.0) m, p = 0.04; detraining group = 454.5 (72.3) vs 515.0 (91.8) m, p = 0.04). There was no significant difference in the six-minute walking test distance in the training group (576.5 (182.5), p > 0.05) and a significant decrease (436.2 (89.6) m, p = 0.04) in the detraining group at the follow-up compared to the third month of aerobic training. No significant difference was observed in quality of life during the study. No complications were found during the protocol of the exercise. These results suggest that long-term aerobic training is safe and can maintain functional capacity in hemodialysis patients. In contrast, detraining can result in loss of functional capacity in these patients.

The Effects of Aerobic Exercise and Detraining on Left Ventricular Cardiomyocyte Apoptosis

Apoptosis can occur in several pathological heart conditions. Physical exercise, particularly aerobic exercise may reduce apoptosis on cardiomyocytes. Detraining can restore adaptation after exercise. This study aimed to see the effect of aerobic exercise and detraining on left ventricular cardiomyocyte apoptosis using caspase-3 as the parameter.This was an in vivo experimental study on Wistar rats Rattus Novergicus. Rats divided to 8 groups: 4 sedentary control groups: 4-week (C4), 8-week (C4D), 12-week (C12), 16-week control (C12D), and 4 aerobic exercise treatment groups: 4-week (A4) and 12-week (A12), and 4 &amp; 12-week post aerobic exercise treatment followed by 4 weeks detraining (A4D, A12D). Caspase-3 protein in rat left ventricular tissue was identified by immunohistochemistry staining. Data were analized with ANOVA test using SPSS proggramme version 20.Data analysis showed an increase percentage of caspase-3 expression on post-aerobic exercise (A), be compared with conntrol group (C) (A4 65,3%±2,54 vs K4 6,4%±1,78, p&lt;0,001; A12 41,8%±3,21 vs K12 5,7%±0,88, p&lt;0,001; A4D 66,6%±1,89 vs K4D 8,6%±3,60, p&lt;0,001; A12D 45,1%±1,50 vs K12D 7,4%±2,06, p&lt;0,001). Percentage of caspase-3 expression was not different on post-aerobc exercise (A), be compare with detraining group (A4D 66,6%±1,89% vs A4 65,4%±2,54, p=0,484; A12D 45,1%±1,50 vs A12 41,8%±3,21, p=0,063). Percentage of caspase-3 expression on post 4-week aerobic exercise group was higher than post12-week aerobic exercise (A4 65,4%±2,54 vs A12 41,8%±3,21, p&lt;0,001).In conclusion, the aerobic exercise protocol used in this study, was not found to decrease left ventricular cardiomyocyte apoptosis. Detraining did not increase left ventricular cardiomyocyte apoptosis.

Detraining Leads to Weight Gain and a Decrease in Hepatic Glycogen after 8 Weeks of Training

Many studies have evaluated the effects of physical training on several metabolic parameters, but few studies have been conducted to evaluate the effects of detraining on these variables. Female mice were distributed into three experimental groups: sedentary controls (C-SED, not trained), trained controls (TR, trained for 10 weeks) and a detraining group (DT, animals detrained for 2 weeks after 8 weeks of training). The exercise protocol was performed by swimming applied for 60 min/day on 5 days/week. The DT group showed an increase of body weight in the 10th week when compared to the 8th week (after training cessation) and the TR group. The groups did not show differences in the plasma levels of corticosterone, glucose, total cholesterol or triglycerides. The DT group showed decreased glycogen content when compared to the TR group. No significant differences were found in the gene expression of glycogen synthase or glycogen phosphorylase or in hepatic glycogen content between CT and TR or DT group. We verified that after a training period of 8 weeks, the animals had an increase in body weight after two weeks of detraining. After two weeks of detraining, animals showed a decrease in liver glycogen content, without an altered fasting glucose concentration in their plasma.

Sudden detraining deteriorates swimming training-induced enhancement of short-term and spatial learning memories in mice

In the present study, we investigated the effect of swimming training and sudden detraining on learning ability and spatial memory capability and on neurogenesis and brain-derived neurotrophic factor (BDNF) expression in the hippocampus of mice. Male ICR mice were randomly assigned into three groups (n= 15 in each group): the control group, the swimming training group, and the detraining group. The mice in the swimming training group were made to swim (6 days/week, 60 min/day) for 8 weeks. The mice in the detraining group were accomplished the same swimming program for 4 weeks and then discontinued exercise for 4 weeks. In the present results, enhanced short-term and spatial learning memories and increased hippocampal neurogenesis and BDNF expression were observed in the mice of the swimming training group. In contrast, decreased short-term and spatial learning memories were observed in the mice of the swimming detraining group compared to the control level. Hippocampal neurogenesis and BDNF expression were also decreased in the mice of the detraining group near to the control level. Here in this study, we suggest that sudden cessation of exercise training might bring decline of the brain functions.

MTOR signaling response to resistance exercise is altered by chronic resistance training and detraining in skeletal muscle

Resistance training-induced muscle anabolism and subsequent hypertrophy occur most rapidly during the early phase of training and become progressively slower over time. Currently, little is known about the intracellular signaling mechanisms underlying changes in the sensitivity of muscles to training stimuli. We investigated the changes in the exercise-induced phosphorylation of hypertrophic signaling proteins during chronic resistance training and subsequent detraining. Male rats were divided into four groups: 1 bout (1B), 12 bouts (12B), 18 bouts (18B), and detraining (DT). In the DT group, rats were subjected to 12 exercise sessions, detrained for 12 days, and then were subjected to 1 exercise session before being killed. Isometric training consisted of maximum isometric contraction, which was produced by percutaneous electrical stimulation of the gastrocnemius muscle every other day. Muscles were removed 24 h after the final exercise session. Levels of total and phosphorylated p70S6K, 4E-BP1, rpS6, and p90RSK levels were measured, and phosphorylation of p70S6K, rpS6, and p90RSK was elevated in the 1B group compared with control muscle (CON) after acute resistance exercise, whereas repeated bouts of exercise suppressed those phosphorylation in both 12B and 18B groups. Interestingly, these phosphorylation levels were restored after 12 days of detraining in the DT group. On the contrary, phosphorylation of 4E-BP1 was not altered with chronic training and detraining, indicating that, with chronic resistance training, anabolic signaling becomes less sensitive to resistance exercise stimuli but is restored after a short detraining period.

Effects of training on body composition, blood lipids, and glucose homeostasis assessed by the homeostasis model assessment

Summary Objective To determine effect of aerobic exercise training on glucose homeostasis, body composition and lipid profile in presence of obesity. Methods A total 34 middle-aged (43 ± 3 years) obese men (BMI = 32.1 ± 2.9 kg/m 2 ) were divided into exercise (3 months aerobic exercise, three times weekly) or control (detraining) group. Fasting glucose, triglyceride (TG), high-density lipoprotein ( HDL ) , beta-cell function and anthropometrical indexes measured before and after aerobic exercise intervention or detraining in exercise and control group respectively. Statistical analysis was performed with the SPSS software version 15.0 using an independent paired t -test. The P -value Results There are no differences in anthropometrical or biochemical variables in baseline in two groups ( P ≥ 0.05). Exercise intervention led to significant decrease in fasting glucose, TG, TG/HDL ratio, systolic blood pressure and all anthropometrical indexes in exercise group ( P P P P ≥ 0.05). Conclusion Despite no significant change on insulin resistance in response to aerobic exercise training in middle-aged obese males, but was associated with an improvement in body composition and lipid profile and particularly fasting glucose in these subjects. It seems that reduction in blood glucose has occurred in response to increased insulin secretion of pancreas beta-cells.

The effects of detraining on blood adipokines and antioxidant enzyme in Korean overweight children

The present study examined the change to clarify the effects of detraining on the concentration of lipid profiles, serum adipokines and antioxidant enzyme gene expression in Korean overweight children. The subjects were normal children (n = 19) and obese children (n = 20) who were further subdivided into the overweight training (OT) group (n = 10) and the overweight detraining (OD) group (n = 10). Maximal oxygen uptake (VO(2)max); body composition; lipid profiles (TG, TC); adipokines (adiponectin and leptin); antioxidants (blood and gene expressions SOD and GPX) were measured before, 12 weeks, and 24 weeks after the exercise program. Body mass index (BMI) and %fat were significantly higher in the OD group only. However, waist hip ration (WHR) and systolic blood pressure (SBP) were significantly decreased in the OT group. TG was significantly decreased in the OT group. There was a significant difference in TG level between the two groups. Besides, adiponectin was significantly increased in both the OT group and the OD group. Furthermore, leptin was significantly decreased in the OT group. There was a significant difference in leptin level between the two groups. In training groups, the expression of SOD was significantly increased after a 12- and 24-week period (p < 0.05). However, detraining group was significantly increased after a 12-week only (p < 0.05). In addition, GPX was significantly increased after a 24-week only in the training group (p < 0.05). Thus, detraining showed that negative effected on body composition and lipid profiles and maintained of uniform period on adipokines and antioxidant enzyme the protein and expression.

The Effects of Plyometric Training Followed by Detraining and Reduced Training Periods on Explosive Strength in Adolescent Male Basketball Players

The aims of this study were to determine the effects of (a) plyometric training on explosive strength indicators in adolescent male basketball players and (b) detraining and reduced training on previously achieved explosive strength gains. Two groups were formed: an experimental and a control group. The former was submitted to a 10-week in-season plyometric training program, twice weekly, along with regular basketball practice. Simultaneously, the control group participated in regular basketball practice only. At the end of this period, the experimental group was subdivided into 2 groups: a reduced training group and a detraining group. All participants were assessed on squat jump, countermovement jump, Abalakov test, depth jump, mechanical power, and medicine ball throw at the beginning and at the end of the 10-week in-season plyometric training and on weeks 4, 8, 12, and 16 of the in-season detraining and reduced training periods. In the first phase of the study, the experimental group significantly increased all the assessed indicators (p < 0.05). In the following phase and in general all the groups maintained the previously achieved results. In conclusion, plyometric training showed positive effects on upper- and lower-body explosive strength in adolescent male basketball players. Moreover, we can state that both detraining and a reduced training program indistinctly contribute to maintenance of strength levels. These results highlight the unique power that basketball-specific training seems to have on the sustainability and maintenance of sport performance.

The Long-term Effects of Progressive Resistance Training on Health-related Quality in Older Adults

This study examined the persistence rate of resistance training after intervention with progressive resistance training and the long-term changes in self-perceived function as Heath-related quality of life (HRQOL) between a maintaining group (TR) and a detraining group (DT) after the intervention. One hundred sixty-seven persons aged 65 and older participated in this study. We measured SF-36 as indices of HRQOL before intervention (T1), after intervention (T2), and 1 year later (T3).We assessed 135 participants at T3, and, of these, 58 were in TR and 77 were in DT. In TR, T2 scores significantly improved over T1 scores for Physical Functioning, Role Physical, and Mental Health (p<.05-.01). Moreover, in T3 scores, Physical Functioning (p<.01) and Role Physical (p<.05) significantly improved over T1 scores. In DT, T2 scores were significantly higher than T1 scores for Vitality and Mental Health (both p<.01), while T3 scores significantly decreased from T2 scores for Physical Functioning, General Health, Vitality, and Mental Health (p<.05-p<.01). Only Physical Functioning of TR was significantly higher than that of DT in T2. However, Physical Functioning, Role Physical, General Health, Vitality, and Mental Health of TR were significantly higher than that of DT in T3 (p<.05-.01). No subscale scores at T3 were significantly lower than at T1. Our findings suggest that for the elderly, voluntarily continuing training after the structured program has beneficial effects for HRQOL, and the differences in HRQOL with regard to how to spend time after the intervention over the long term. However, it was possible for the HRQOL of the participants to deteriorate, though not significantly, at 1 year after the intervention in comparison to the baseline. This result suggests that the significant HRQOL gains of the DT group for the intervention period are very important.

Detraining Produces Minimal Changes in Physical Performance and Hormonal Variables in Recreationally Strength-Trained Men

The object of this study was to examine changes in muscular strength, power, and resting hormonal concentrations during 6 weeks of detraining (DTR) in recreationally strength-trained men. Each subject was randomly assigned to either a DTR (n = 9) or resistance training (RT; n = 7) group after being matched for strength, body size, and training experience. Muscular strength and power testing, anthropometry, and blood sampling were performed before the experimental period (T1), after 3 weeks (T2), and after the 6-week experimental period (T3). One-repetition maximum (1RM) shoulder and bench press increased in RT at T3 (p < 0.05), whereas no significant changes were observed in DTR. Peak power output and mean power output significantly decreased (9 and 10%) in DTR at T2. Peak torque of the elbow flexors at 90° did not change in the RT group but did significantly decrease by 11.9% at T3 compared with T1 in the DTR group. Vertical jump height increased in RT at T2 but did not change in DTR. Neither group displayed any changes in 1RM squat, body mass, percent body fat, or resting concentrations of growth hormone, follicle-stimulating hormone, luteinizing hormone, sex hormone-binding globulin, testosterone, cortisol, or adrenocorticotropin. These data demonstrate that 6 weeks of resistance DTR in recreationally trained men affects power more than it does strength without any accompanying changes in resting hormonal concentrations. For the recreational weight trainer, losses in strength over 6 weeks are less of a concern compared with anaerobic power and upper arm isometric force production. Anaerobic power exercise with a high metabolic component coming from glycolysis might be of importance for reducing the impact of DTR on Wingate power performances. A minimal maintenance training program is recommended for the recreational lifter to offset any reductions in performance.

Maintenance of whole muscle strength and size following resistance training in older men.

Following a progressive resistance training (PRT) program of 3 days per week, we sought to examine how effective a resistance training maintenance program of 1 day per week would be to preserve muscle strength and size in older men. Each subject's whole muscle strength (1 repetition maximum, or 1RM) and whole muscle size (determined by computed tomography scan) were measured before (T1) and after (T2) 12 weeks of PRT and again following 6 months (T3) of training (TR) or detraining (DT). During the 12-week PRT, older men (N = 10; age 70 +/- 4 years) trained their knee extensors 3 days per week at 80% of their 1RM. The maintenance program consisted of older men (n = 5; TR; 75 +/- 1 years) who completed 3 sets of 10 repetitions at 80% of their 1RM 1 day per week (this was equivalent to a single training session that was performed 3 days per week during the 12-week PRT). The other group of older men (n = 5; DT; 69 +/- 1 years) resumed their normal lifestyle (no regular physical activity) following the 12-week PRT. From T1 to T2, muscle strength increased (p <.05) 45% (66 +/- 10 to 94 +/- 10 kg) in the TR group and 53% (50 +/- 6 to 74 +/- 7 kg) in the DT group. From T2 to T3, whole muscle strength of the TR group was unchanged (96 +/- 11 kg), whereas strength decreased (p <.05) in the DT group by 11% (66 +/- 6 kg). Muscle size demonstrated a similar pattern with a 7% increase (p <.05) in both groups from T1 to T2. No change in muscle size was found in the TR group from T2 to T3, whereas the DT group had a 5% reduction (p <.05). These data indicate that resistance training 1 day per week was sufficient to maintain muscle strength and size in these older men following a 12-week PRT program. Furthermore, the men who resumed their normal lifestyle (no regular physical activity) experienced significant losses in muscle strength and size.

Detraining Produces Minimal Changes in Physical Performance and Hormonal Variables in Recreationally Strength-Trained Men

The object of this study was to examine changes in muscular strength, power, and resting hormonal concentrations during 6 weeks of detraining (DTR) in recreationally strength-trained men. Each subject was randomly assigned to either a DTR (n = 9) or resistance training (RT; n = 7) group after being matched for strength, body size, and training experience. Muscular strength and power testing, anthropometry, and blood sampling were performed before the experimental period (T1), after 3 weeks (T2), and after the 6-week experimental period (T3). One-repetition maximum (1RM) shoulder and bench press increased in RT at T3 (p </= 0.05), whereas no significant changes were observed in DTR. Peak power output and mean power output significantly decreased (9 and 10%) in DTR at T2. Peak torque of the elbow flexors at 90 degrees did not change in the RT group but did significantly decrease by 11.9% at T3 compared with T1 in the DTR group. Vertical jump height increased in RT at T2 but did not change in DTR. Neither group displayed any changes in 1RM squat, body mass, percent body fat, or resting concentrations of growth hormone, follicle-stimulating hormone, luteinizing hormone, sex hormone-binding globulin, testosterone, cortisol, or adrenocorticotropin. These data demonstrate that 6 weeks of resistance DTR in recreationally trained men affects power more than it does strength without any accompanying changes in resting hormonal concentrations. For the recreational weight trainer, losses in strength over 6 weeks are less of a concern compared with anaerobic power and upper arm isometric force production. Anaerobic power exercise with a high metabolic component coming from glycolysis might be of importance for reducing the impact of DTR on Wingate power performances. A minimal maintenance training program is recommended for the recreational lifter to offset any reductions in performance.

Effects of exercise training on plasminogen activator inhibitor activity

Plasminogen activator inhibitor (PAI) activity, an important regulator within the fibrinolytic system, has been shown to be a risk indicator for venous and arterial thrombosis. The present study aimed to test the effects of exercise training on PAI activity, and to link possible changes in PAI activity to changes in cardiovascular fitness, body composition, and the lipid profile. Four groups of previously sedentary subjects were studied thrice in an 8-month period. A long-term training group (N = 11) trained during the entire 8-month period. A detraining group (N = 14) trained for 4 months and then reverted to sedentary habits. A postponed training group (N = 16) trained only during the second 4-month period, and a no-training control group (N = 9) remained untrained throughout the entire 8-month period. PAI activity always decreased in response to training, but the training effects were small and spontaneous seasonal shifts in PAI activity of the control groups clouded their interpretation. Furthermore, detraining failed to influence PAI activity and training-induced changes in PAI activity were not related to simultaneous changes in maximal oxygen consumption, diastolic blood pressure, triglycerides, or percentage body fat, and inconsistently related to the training-induced changes in LDL-cholesterol and HDL-cholesterol. The occurrence of simultaneous changes in body fat, blood pressure, and the lipid profile underscores the potential of regular exercise to protect against cardiovascular disease. Whether these beneficial effects are accompanied by changes in the fibrinolytic system remains to be proven.