Prescribing load at the peak power output (PPO) is one of the strategies utilized to enhance lower-body muscle power. PPO of an exercise is determined based on a relative percentage of the ...one-repetition maximum test (1RM). However, 1RM tests may be impractical in some weightlifting derivatives. This study aimed to identify the PPO of the hang power clean (HPC), hang high pull (HHP), and mid-thigh clean pull (MTCP) based on a relative percentage of body mass (BM).
Fifteen males with weightlifting experience performed HPC, HHP, and MTCP at loads ranging from 30-90% BM. Kinematic data were collected through a 16-camera infrared motion capture system and processed based on a three-dimensional lower-extremity model. Ground reaction force (GRF) data were collected from two force plates. PPO was calculated as the product of model center of mass velocity and combined vertical GRF during the concentric phase.
PPO occurred at 90% BM for the HPC. In addition, the PPO occurred at 90% BM for the HHP and it was not different than 70% and 80% BM. At last, the PPO for MTCP occurred at 80% BM and it was not different than 60% and 70% BM.
Relative percentages of BM can be used to determine PPO in the HPC, HHP, and MTCP. PPO during HPC is achieved at 90% BM, while the PPO for HHP and MTCP is achieved between 70% to 90% BM and 60 to 80% BM, respectively.
Background: For decades the literature has been investigating the ideal dose-response regarding the frequency, intensity and volume of training that optimize the increase in muscle strength and power ...in athletes and non-athletes. Objective: Evaluate the effects of strength training from a nonlinear (NLP) and non-periodized (NP) model on muscular peak power in soccer players. Methods: Twelve male junior football players from a professional team in Cabo Frio (Brazil) were recruited and randomly divided into two groups (6 in each group). The groups were randomly divided into: G1 - (Body mass: 64.7 ± 6.5 kg; Height: 172.3 ± 5.8 cm; % fat: 5.1 ± 2.7; Age: 17.5 ± 1.0 years) performed RT with NLP model; G2 - (Body mass: 66.1 ± 4.7; Height: 177.1 ± 6.1 cm; % fat: 5.1 ± 1.2, age: 17.6 ± 0.5 years) performed RT with NP model. Both groups are subjected to 12 weeks of training. PNL strength training consisted of weight training sessions on alternate days, 3 times a week, the rest intervals were 120s among the exercises and included 10 exercises. NLP distribution was as follows: Day 1 (3x4-6 maximum repetitions RM with rest intervals of 120 sec between sets); Day 2 (3x8-10RM with 60-90 rest intervals between sets); and day 3 (3x12-15RM with rest intervals of 60 sec between sets). NP training performed the same duration, weekly frequency, exercises and number of sets (3 sets 8-10RM and 60-90 sec rest intervals). Before and after NP and NLP training, muscle peak, speed and agility were evaluated. Results: The ANOVA with mixed model showed no significant interaction between group and moment (F(1,10) = 0.133; p=0.72), and no significant main effect for group (F(1,10) = 0.032; p=0.86) in muscular peak power. There was a significant main effect for moment (F(1,10) = 14.872; p=0.003), where were showed that Post-training presented higher values of muscular peak power compared to Baseline (p= 0.003). Conclusion: It is concluded that both training organization models are effective and can be used to develop peak muscle power.
This study aims to analyze the effect of curcumin on serum levels of creatine kinase (CK) and malondialdehyde (MDA) after 24 hours of high-intensity physical exercise. This experimental study used a ...pre and post-control group design. A total of 18 healthy men with an average age of 23 years participated in this study. Subjects were selected using a random sampling technique and then the subjects were divided into 2 groups, namely the group given a placebo and the group given curcumin at a dose of 400 mg. On the first day, all subjects took data on the characteristics of the research subjects, and then the subjects did the high-intensity physical exercise in the form of squad and leg press exercises with an intensity of 80-90% of maximum ability. On the second day, after 24 hours, all subjects took pre-test data samples to measure serum CK and MDA levels, then the intervention was given based on their respective groups. On the third day, after 24 hours, all subjects took post-test blood samples to measure CK and MDA serum levels. Blood samples were analyzed in the laboratory using the ELISA method. The results of this study reported that the group given a placebo did not significantly reduce serum CK levels, while the group with curcumin at a dose of 400 mg could significantly reduce CK levels (p<0.05). Furthermore, there was no significant decrease in serum MDA levels in the placebo group or the curcumin group (p>0.05). It can be concluded that the administration of curcumin after 24 hours after high-intensity weight training was able to reduce serum CK levels without a decrease in MDA serum levels. Since the decrease in serum CK levels is an essential part of recovery during muscle damage. Therefore, curcumin is recommended to be taken after 24 hours after exercise to speed up recovery.
High School Weight Room Safety Stocz, Mike; Holt, William R
Journal of physical education, recreation & dance,
01/2021, Letnik:
92, Številka:
3
Journal Article
Recenzirano
Joseph Pruitt was a cross-country athlete who participated at Los Lunas High School. The team would use a school-furnished weight room with the understanding that the athletes would use a spotter for ...any free weights, benches, and/or machines. Pruitt was performing sit-ups, while holding a twenty-five-pound weight, on a bench without a spotter. After completing the exercise, Pruitt slipped while attempting to get off the bench, which caused the weight to fall onto, and crush, one of his fingers. After multiple surgeries, Pruitt filed suit, claiming that the defendants had an unwritten rule of not providing spotters for athletes completing exercises within the weight room.
Introduction and hypothesis
Women who perform high-impact activities might be at greater risk of pelvic floor dysfunction (PFD) than those participating in low-impact exercise; however, little is ...known about whether PFD is more common in one type of high-impact activity than another. The aim of this study was to compare the prevalence of PFD symptoms in women who engage in high-impact activity compared with CrossFit®-brand training (CF).
Methods
An online survey collected data from 1,379 women (521 runners, 858 CF) on exercise participation, parity, and PFD symptoms, via the Pelvic Floor Distress Inventory (PFDI-20). Specific questions from each PFDI-20 subscale further investigated symptoms of pelvic organ prolapse (POP), anal incontinence (AI), as well as stress (SUI) and urgency (UUI) urinary incontinence.
Results
Symptoms of POP and AI were significantly higher in runners (POP 12.7%, AI 34.0%) than in CF (POP 7.8%,
p
= 0.003; AI 27.7%,
p
= 0.014). There was no significant difference in SUI symptoms between groups (37.0% vs 41.0% respectively,
p
= 0.141). Vaginally parous runners reported significantly more symptoms of POP (19.0% vs 12.2%,
p
= 0.023), AI (39.3% vs 27.2%,
p
= 0.001), and UUI (36.3% vs 29.0%,
p
= 0.037) than CF.
Conclusion
Women, particularly parous women, who participate in running, have a higher prevalence of POP and AI symptoms than women who participate in CF. This suggests that CrossFit®-brand training might not be more detrimental to PFD symptoms than other high-impact activity, such as running. This study does not conclude a pelvic floor health benefit of one exercise over another, but highlights that exercise options can be provided to women.
ABSTRACTSjöberg, H, Aasa, U, Rosengren, M, and Berglund, L. Content validity index and reliability of a new protocol for evaluation of lifting technique in the powerlifting squat and deadlift. J ...Strength Cond Res 34(9)2528–2536, 2020—The aim of the study was to create a protocol to cover aspects of technique considered to be associated with risk of injury in the powerlifting squat and deadlift and to examine the content validity and reliability of the aspects included in the protocols. For the content validity investigation, a consensus group of 3 powerlifting physiotherapists identified the domains of content (risk of injury) for 2 protocols (1 for squat and 1 for deadlift) of essential aspects of lifting technique through discussions and a review of the literature. Eight selected powerlifting experts rated the relevance of each aspect in relation to risk of injury (acute or by overuse), and a quantitative estimate of the content validity of each aspect was measured through calculations of a Content Validity Index (CVI). Aspects of low content validity were discarded, and the remainders were evaluated for their inter-rater and intra-rater reliability among 4 experienced powerlifters used to coaching and evaluating powerlifting technique. The reliability was calculated and analyzed with kappa and percentage of agreement. The final protocols included 17 aspects of squat technique and 10 aspects of deadlift technique that showed good to excellent CVI and percentage of agreement between 64 and 100%. The protocols, formed in this study, will provide evidence-based recommendations on safe lifting technique for coaches and strength practitionersʼ to use to make relevant assessments and instructions.
UCLA Swimmer Lowers the Bar Petersen, Jeremy C
Journal of physical education, recreation & dance,
01/2016, Letnik:
87, Številka:
1
Journal Article
Recenzirano
A university women's swim team was engaged in a routine weight-training circuit workout when one athlete accidentally dropped her weights on a teammate. The injured party filed suit against her ...teammate because of her belief that she did not assume the risk of being harmed by dropped weights while doing push-ups.
Background
Weightlifting training (WLT) is commonly used to improve strength, power and speed in athletes. However, to date, WLT studies have either not compared training effects against those of ...other training methods, or been limited by small sample sizes, which are issues that can be resolved by pooling studies in a meta-analysis. Therefore, the objective of this systematic review with meta-analysis was to evaluate the effects of WLT compared with traditional resistance training (TRT), plyometric training (PLYO) and/or control (CON) on strength, power and speed.
Methods
The systematic review included peer-reviewed articles that employed a WLT intervention, a comparison group (i.e. TRT, PLYO, CON), and a measure of strength, power and/or speed. Means and standard deviations of outcomes were converted to Hedges’
g
effect sizes using an inverse variance random-effects model to generate a weighted mean effect size (ES).
Results
Sixteen studies were included in the analysis, comprising 427 participants. Data indicated that when compared with TRT, WLT resulted in greater improvements in weightlifting load lifted (4 studies,
p
= 0.02,
g
= 1.35; 95% CI 0.20–2.51) and countermovement jump (CMJ) height (9 studies,
p
= 0.00,
g
= 0.95; 95% CI 0.04–1.87). There was also a large effect in terms of linear sprint speed (4 studies,
p
= 0.13,
g
= 1.04; 95% CI − 0.03 to 2.39) and change of direction speed (CODS) (2 studies,
p
= 0.36,
g
= 1.21; 95% CI − 1.41 to 3.83); however, this was not significant. Interpretation of these findings should acknowledge the high heterogeneity across the included studies and potential risk of bias. WLT and PLYO resulted in similar improvements in speed, power and strength as demonstrated by negligible to moderate, non-significant effects in favour of WLT for improvements in linear sprint speed (4 studies,
p
= 0.35,
g
= 0.20; 95% CI − 0.23 to 0.63), CODS (3 studies,
p
= 0.52,
g
= 0.17; 95% CI − 0.35 to 0.68), CMJ (6 studies,
p
= 0.09,
g
= 0.31; 95% CI − 0.05 to 0.67), squat jump performance (5 studies,
p
= 0.08,
g
= 0.34; 95% CI − 0.04 to 0.73) and strength (4 studies,
p
= 0.20,
g
= 0.69; 95% CI − 0.37 to 1.75).
Conclusion
Overall, these findings support the notion that if the training goal is to improve strength, power and speed, supplementary weightlifting training may be advantageous for athletic development. Whilst WLT and PLYO may result in similar improvements, WLT can elicit additional benefits above that of TRT, resulting in greater improvements in weightlifting and jumping performance.
Although growing attention has been drawn to attainable, high-intensity intermittent exercise (HIE)-based intervention, which can improve cardiovascular and metabolic health, for sedentary ...individuals, there is limited information on the impact and potential benefit of an easily attainable HIE intervention for cognitive health. We aimed to reveal how acute HIE affects executive function focusing on underlying neural substrates. To address this issue, we examined the effects of acute HIE on executive function using the color-word matching Stroop task (CWST), which produces a cognitive conflict in the decision-making process, and its neural substrate using functional near infrared spectroscopy (fNIRS). Twenty-five sedentary young adults (mean age: 21.0 ± 1.6 years; 9 females) participated in two counter-balanced sessions: HIE and resting control. The HIE session consisted of two minutes of warm-up exercise (50 W load at 60 rpm) and eight sets of 30 s of cycling exercise at 60% of maximal aerobic power (mean: 127 W ± 29.5 load at 100 rpm) followed by 30 s of rest on a recumbent-ergometer. Participants performed a CWST before and after the 10-minute exercise session, during both of which cortical hemodynamic changes in the prefrontal cortex were monitored using fNIRS. Acute HIE led to improved Stroop performance reflected by a shortening of the response time related to Stroop interference. It also evoked cortical activation related to Stroop interference on the left-dorsal-lateral prefrontal cortex (DLPFC), which corresponded significantly with improved executive performance. These results provide the first empirical evidence using a neuroimaging method, to our knowledge, that acute HIE improves executive function, probably mediated by increased activation of the task-related area of the prefrontal cortex including the left-DLPFC.
•We establish an attainable acute high-intensity intermittent exercise (HIE) model.•We examine how acute HIE affects executive performance using a Stroop task.•We investigate the neural substrate for HIE-induced behavioral changes with fNIRS.•HIE-improved performance is related with boosted dorsolateral prefrontal activation.•HIE improves executive function in relation with task-related prefrontal activation.
Background
Strength training set organisation and its relationship to the development of muscular strength have yet to be clearly defined. Current meta-analytical research suggests that different ...population groups have distinctive muscular adaptations, primarily due to the prescription of the strength training set dose.
Objectives
We conducted a meta-analysis with restrictive inclusion criteria and examined the potential effects of low (LWS), medium (MWS) or high weekly set (HWS) strength training on muscular strength per exercise. Secondly, we examined strength gain variations when performing multi-joint or isolation exercises, and probed for a potential relationship between weekly set number and stage of subjects’ training (trained versus untrained).
Methods
Computerised searches were performed on PubMed, MEDLINE, SWETSWISE, EMBASE and SPORTDiscus™ using the terms ‘strength training’, ‘resistance training’, ‘single sets’, ‘multiple sets’ and ‘volume’. As of September 2016, 6962 potentially relevant studies were identified. After review, nine studies were deemed eligible per pre-set inclusion criteria. Primary data were pooled using a random-effect model. Outcomes for strength gain, strength gain with multi-joint and isolation exercise were analysed for main effects. Sensitivity analyses were calculated for several subgroups by separating the data set and by calculation of separate analyses for each subgroup. Heterogeneity between studies was assessed using the Cochran
Q
and
I
2
statistics.
Results
Pre- versus post-training strength analysis comprised 61 treatment groups from nine studies. For combined multi-joint and isolation exercises, pre- versus post- training strength gains were greater with HWS compared with LWS mean effect size (ES) 0.18; 95% CI 0.06–0.30;
p
= 0.003. The mean ES for LWS was 0.82 (95% CI 0.47–1.17). The mean ES for HWS was 1.01 (95% CI 0.70–1.32). Separate analysis of the effects of pre- versus post-training strength for LWS or MWS observed marginally greater strength gains with MWS compared with LWS (ES 0.15; 95% CI 0.01–0.30;
p
= 0.04). The mean ES for LWS was 0.83 (95% CI 0.53–1.13). The mean ES for MWS was 0.98 (95% CI 0.62–1.34). For multi-joint exercises, greater strength gains were observed with HWS compared with LWS (ES 0.18; 95% CI 0.01–0.34;
p
= 0.04). The mean ES for LWS was 0.81 (95% CI 0.65–0.97). The mean ES for HWS was 1.00 (95% CI 0.77–1.23). For isolation exercises, greater strength gains were observed with HWS compared with LWS (ES 0.23; 95% CI 0.06–0.40;
p
= 0.008). The mean ES for LWS was 0.95 (95% CI 0.30–1.60). The mean ES for HWS was 1.10 (95% CI 0.26–1.94). For multi-joint and isolation exercise-specific one repetition maximum (1 RM), marginally greater strength gains were observed with HWS compared with LWS (ES 0.14; 95% CI −0.01 to 0.29;
p
= 0.06). The mean ES for LWS was 0.80 (95% CI 0.47–1.13). The mean ES for HWS was 0.97 (95% CI 0.68–1.26).
Conclusion
This meta-analysis presents additional evidence regarding a graded dose–response relationship between weekly sets performed and strength gain. The use of MWS and HWS was more effective than LWS, with LWS producing the smallest pre- to post-training strength difference. For novice and intermediate male trainees, the findings suggest that LWSs do not lead to strength gains compared with MWS or HWS training. For those trainees in the middle ground, not a novice and not advanced, the existing data provide a relationship between weekly sets and strength gain as set configurations produced different pre- to post-training strength increases. For well trained individuals, the use of either MWS or HWS may be an appropriate dose to produce strength gains.
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