Randomization versus matching method in resistance training research: A simulation study based on maximal isometric squat strength recovery data

WOS: 000344728100008BACKGROUND: The randomization method (RM) is used as a gold standard for creating equal groups in most independent-group design studies. OBJECTIVE: To identify whether the fatigue index (FI)-based matching method could be an alternative for the RM in the context of forming equal independent study groups using relative maximal isometric squat strength (R-MISS) recovery data as the dependent variable. METHODS: Baseline R-MISS values of 30 resistance-trained male participants were assessed. FI was calculated during an exhaustive training intervention (ETI), including four sets of submaximal isometric squat contractions. Maximal isometric squats were performed 30 seconds, and 2, 4, 6, 8, 10, 12, and 14 minutes after the ETI to assess the recovery levels of R-MISS. For the statistical analyses, low-and high-endurance groups, and two equal-endurance groups (each including 15 participants) were retrospectively formed based on FI scores. RESULTS: The results of the repeated-measures analysis of variance revealed that recovery moments greatly differed (8 minutes) between the high-and low-endurance groups but were similar between the two equal-endurance groups (difference of 2 minutes). Simulations performed using the resampling procedure revealed that the FI-based matching method was more successful than the RM (71.6% vs. 56.2%) in the context of forming equal study groups. CONCLUSIONS: These results indicate that the FI-based matching method is a better alternative to the RM for preventing an unequal distribution of participants among independent groups in R-MISS recovery-related studies

Avoiding Systematic Errors in Isometric Squat-Related Studies without Pre-Familiarization by Using Sufficient Numbers of Trials

WOS: 000343909900020PubMed ID: 25414753There is no scientific evidence in the literature indicating that maximal isometric strength measures can be assessed within 3 trials. We questioned whether the results of isometric squat-related studies in which maximal isometric squat strength (MISS) testing was performed using limited numbers of trials without pre-familiarization might have included systematic errors, especially those resulting from acute learning effects. Forty resistance-trained male participants performed 8 isometric squat trials without pre-familiarization. The highest measures in the first "n" trials (3 = 24) could be an effective means of obtaining the actual MISS values of the participants. The common use of a limited number of trials in MISS tests without pre-familiarization appears to have no solid scientific base. Our findings suggest that the number of trials should be increased in commonly used MISS tests to avoid learning effect-related systematic errors

Relationship Between Fatigue Index and Number of Repetition Maxima with Sub-Maximal Loads in Biceps Curl

WOS: 000325555700018PubMed ID: 24235992The aim of this study was to investigate the relationship between the number of repetition maxima to volitional failure (RM) at 60%, 75%, 90% of 1RM and fatigue index (FI), a determinant of the muscular endurance level. Thirty four resistance trained male participants attended two testing sessions. The first session was conducted to assess 1RM load and RM at 60%, 75% and 90% of 1RM in the supine biceps curl (SBC) exercise. In the second session, a FI test protocol consisting of five sets of SBC with 90 s rest between sets was performed to determine FI values. Each set was performed to volitional failure using a sub-maximal load in the range of 15-20RM. Hypothetical high FI and low FI groups (17 participants with the highest and lowest FI values, respectively) were formed for statistical analyses. ANOVA results revealed that RM at 60%, 75%, 90% of 1RM were not significantly different between FI groups when controlled for mean repetition tempo (p=0.11, p=0.38, p=0.13, respectively). Pearson's correlation coefficients revealed that no significant relationship was present between FI values and RM at 60%, 75%, 90% of 1RM (p=0.40, p=0.46, p=0.14, respectively). In conclusion, the muscular endurance level of participants defined in terms of FI value was not an indicator of RM in SBC. Therefore, athletes with different muscular endurance levels can use similar percentages of 1RM in biceps curl exercise in their training programs when the aim is to elicit training adaptations related to specific RM zones

Effects of carbohydrate and caffeine combination mouth rinse on anaerobic performance of highly trained male athletes

The ergogenic effects of carbohydrate (CHO) and caffeine (CAF) mouth rinse (MR) methods on anaerobic performance remains unclear. Therefore, the aim of this study was to investigate the effects of CHO, CAF, and CHO + CAF combination solutions in mouth on repeated vertical jumping (RVJ) performance in highly trained male athletes. Eight male athletes (mean age: 22 years) underwent test sessions four times with minimum 24-h intervals under fasting conditions. Participants rinsed their mouths with four different 25-ml solutions, namely, CHO (6.4% maltodextrin = 1.6 g), CAF (1.2% caffeine = 300 mg), placebo (PLA, saccharin), or CHO + CAF (6.4%+1.2%) combination, for 10 s and performed a 30-s RVJ test twice with a 5-min interval. Peak power output, vertical jump height, blood lactate level, fatigue index, and rate of perceived exertion of the RVJ tests for different intervention sessions were compared. The statistical significance level was set at p 0.05, g < 0.94). Our study did not elicit sufficient evidence to recommend highly trained male athletes the use of CHO- and CAF-MR separately or in combination to enhance jump performance. However, the fact that some differences have medium to large effect sizes suggests that the issue is still worth to be a potential topic for further research

Residual effects of static stretching and self-myofascial-release exercises on flexibility and lower body explosive strength in well-trained combat athletes

WOS: 000401912800008BACKGROUND: The self-myofascial technique is a new exercise modality that is thought to improve muscular performance and restore soft tissue. However, there are limited empirical data demonstrating the efficacy of this technique on athletic performance. OBJECTIVE: The purpose of this study was to determine the effects of self-myofascial-releasing exercises on the residual characteristics of the sit and reach (S&R) and countermovement jump (CMJ) performance in well-trained combat athletes. METHODS: Sixteen well-trained male combat athletes (age: 23.9 +/- 3.6 years, mass: 78.78 +/- 10.41 kg, combat experience: 12.87 +/- 5.23 years) performed three exercise sessions called "aerobic running (AR)", "aerobic running combined with static stretching (AR + SS)", and " aerobic running combined with self-myofascial release (AR + SMR)" at 48 hour intervals in a randomized crossover design. After each session, the subjects performed the S&R and CMJ tests successively with 30-s of rest between the tests at the 15th second and at the 2nd, 4th, 6th, 8th, 10th, 15th, and 30th minute during the recovery period. RESULTS: ANOVA and the post-hoc LSD (Least Significant Difference) test revealed that the AR + SMR treatment increased the flexibility greater than AR + SS (p = 0.029) at the 45th second. Additionally, the AR + SMR treatment resulted in less of a decrease in CMJ height compared to AR + SS at the 10th minute (p = 0.025). A larger decrease in the CMJ height was found after AR + SS compared to the AR and AR + SMR treatments at the 10th and 15th minute, respectively (p = 0.025 and p = 0.038). These results revealed that SMR had no advantage over AR and SS in terms of enhancing flexibility. A statistically insignificant inhibitory effect of SMR was detected on the CMJ performance. SS appeared to have an inhibitory effect on the CMJ performance for approximately 15 minutes. CONCLUSION: SMR may have a detrimental effect on CMJ performance. Trainers or athletes should consider using the SMR technique before training or competition to prevent possible power decrement