Strength Training Period Research Articles

Can the cross-education of strength attenuate the impact of detraining after a period of strength training? A quasi-randomized trial

PurposeUnilateral strength training may attenuate the decline in muscle strength and size in homologous, contralateral muscles. This study aimed to determine whether the cross-education of strength could specifically attenuate the effects of detraining immediately after a short (prehabilitation-type) period of strength training.MethodsTwenty-six strength-trained participants were assigned to either four weeks of unilateral strength training of the stronger arm (UNI) or detraining (Detrain). Motor evoked potential (MEP) and cortical silent period (cSP) responses, muscle cross-sectional area (CSAFlexor; peripheral quantitative computed tomography) and maximal strength, rate of force development (RFD) and muscle activation (EMG) were examined in both elbow flexors before and after the intervention period.ResultsIn UNI, one-repetition maximum (1-RM) strength improved in both the trained (∆ = 2.0 ± 0.9 kg) and non-trained (∆ = 0.8 ± 0.9 kg) arms despite cessation of training of the weaker arm, whereas 1-RM strength was unchanged in Detrain. Maximal voluntary isometric contraction, isokinetic peak torque, and RFD did not change in either group. No neural changes were detected in UNI, but cSP increased in Detrain (∆ = 0.010 ± 0.015 s). CSAFlexor increased in the trained arm (∆ = 51 ± 43 mm2) but decreased in the non-trained arm (∆ = -53 ± 50 mm2) in UNI. CSAFlexor decreased in both arms in Detrain and at a similar rate to the non-trained arm in UNI.ConclusionUNI attenuated the effects of detraining in the weaker arm as shown by the improvement in 1-RM strength. However, the cross-education of strength did not attenuate the decline in muscle size in the contralateral arm.

Influence of resistance training on ambulatory blood pressure monitoring: a brief review

Arterial hypertension is considered a primary risk factor in the development of cardiovascular diseases. An effective non-pharmacological strategy against arterial hypertension is the practice of physical exercises. However, issues remain about the ambulatory behavior of blood pressure after different training protocols, especially strength exercises. In this sense, the objective of this study was to review and summarize the main results found in the literature that investigated the effects of strength training (isolated and associated with other interventions) on ambulatory blood pressure monitoring. A search was carried out in the free databases PubMed, Lilacs and Google Scholar, using the keywords in different combinations. Studies in the English language were considered, which investigated ambulatory blood pressure monitoring after acute strength training, after a period of strength training alone and/or in association with other interventions. To sum up, strength training (isolated and combined) is an essential measure for lowering blood pressure and improving/maintaining vascular health. The combination of different training strategies in a periodized manner can be adopted to generate broader benefits in hemodynamic measurements. An important point that was observed in the studies is that strength training can be implemented as an interesting option for those individuals who cannot do aerobics training, especially for the older people who need to stimulate the neuromuscular system. It can help with other benefits, such as blood pressure control, mood improvement, sleep quality, among others.

The effects of 8-week complex training on lower-limb strength and power of Chinese elite female modern pentathlon athletes.

Complex training (CT) is a combination training method that alternates between performing high-load resistance training (RT) and plyometric training within one single session. The study aimed to examine the effects of CT on lower-limb strength and power of elite female modern pentathlon athletes under the new modern pentathlon format and competition rules. Ten female participants (age: 23.55 ± 2.22 years, weight: 60.59 ± 3.87 kg, height: 169.44 ± 4.57 cm, and training experience: 6.90 ± 2.08 years) of the national modern pentathlon team completed 8 weeks of RT as followed by 8 weeks of CT, with 2 weeks of break. Then, the participants conducted 8 weeks of CT, which included RT combined with plyometric training (e.g., drop jump and continuous jump). All stages of training were designed by the linear strength training period theories, requiring participants to train twice for the first 4 weeks and three times for the second 4 weeks. The one-repetition maximum (1RM) of squat, isometric mid-thigh pull (IMTP), counter-movement jump (CMJ), squat jump (SJ), pre-stretch augmentation percentage (PSAP), and reaction strength index (RSI) were assessed before and after both RT and CT training. One-way repeated-measure ANOVA models revealed that the 1RM of squat was significantly improved (p < 0.001) after RT as compared to pre-RT. No significant improvement in IMTP (p = 0.055), CMJ (p = 0.194), SJ (p = 0.692), PSAP (p = 0.087), and RSI (p = 0.238) was not observed. After CT, 1RM of squat (p < 0.001), IMTP (p < 0.035), CMJ (p < 0.001), SJ (p < 0.008), RSI (p < 0.006) were significant improved as compared to pre-RT, post-RT and pre-CT, while significant improvements in PSAP were observed as compared to pre-RT (p = 0.003) and pre-CT (p = 0.027), but not to post-RT (p = 0.156). This pilot study showed the promise of CT following RT to improve lower-limb strength and power in elite female modern pentathlon athletes. The findings are worthwhile to be confirmed in future studies with larger sample size and randomized design.

Resistance training-induced improvement in physical function is not associated to changes in endocrine somatotropic activity in prefrail older adults

ContextResistance training improves muscle function in prefrail and frail elderly. The role of the somatotropic axis in this physiologic process remains unclear. Insulin-like growth factor I (IGF-I) and its associated proteins Insulin-like growth factor binding protein 3 (IGFBP3) and acid labile subunit (ALS) build a circulating ternary complex that mediates growth hormone (GH) effects on peripheral organs and can serve as a measure of endocrine somatotropic activity. ObjectiveThe aim of this study was to assess the association between resistance training-induced changes in physical performance and basal levels of IGF-I, IGFBP-3 and ALS in prefrail older adults. Methods69 prefrail community-dwelling older adults, aged 65 to 94 years, were randomly assigned to a 12-week period of strength or power training or to a control group. The study was registered at clinicaltrials.gov as NCT00783159. Serum concentrations of IGF-I, IGFBP-3 and ALS were measured at rest before and after the intervention. Hormonal differences were examined in relation to changes in physical performance assessed by the Short Physical Performance Battery (SPPB). ResultsWhile resistance training led to significant improvements in SPPB score it did not induce significant differences in somatotropic hormone concentrations. Pre- and post-intervention changes in IGF-I, IGFBP-3, ALS or IGF/IGFBP-3 molar ratio were not related to the intervention mode, even after adjustment for age, sex, nutritional status, as well as SPPB and hormone concentrations at baseline. ConclusionTraining-induced improvements in physical performance in prefrail older adults were not associated with significant changes in endocrine somatotropic activity.

Efficacy and Safety of a Combined Aerobic, Strength and Flexibility Exercise Training Program in Patients with Implantable Cardiac Devices.

Purpose: The “FIDE Project” (Fitness Implantable DEvice) was organized by the Institute of Sports Medicine and Science and the World Society of Arrhythmias with the aim of demonstrating the usefulness of exercise training in improving functional capacity in patients with implantable cardiac devices. Materials and Methods: Thirty sedentary patients were selected for the project (25 males and 5 females), with a mean age of 73 ± 5 years (range 44–94 years). Twenty-five were implanted with a Pacemaker (PM) and five with an Implantable Cardioverter Defibrillator (ICD). Atrial fibrillation/atrial flutter was present in ten (34%) patients, post-ischemic dilated cardiomyopathy in five (17.2%), sick sinus syndrome in six (20,7%), complete atrium-ventricular block in six (20.7%), hypertrophic cardiomyopathy in one (3.4%) and recurrent syncope in one (3.4%). The baseline assessment comprised cardiovascular examination, resting and stress ECG, cardiopulmonary exercise testing (V ˙O2peak), strength assessment of different muscle groups, and a flexibility test. The same measurements were repeated after 15–20 consecutive training sessions, over a 2-month period. The exercise prescription was set to 70–80% of HRR (Heart rate reserve) and to 50–70% of 1RM (1-repetition maximum, muscular force). The training protocol consisted of two training sessions per week performed in our institute, 90 min for each (warm-up, aerobic phase, strength phase and stretching) and one or more at home autonomously. Results: The cardiopulmonary testing after the training period documents a significant improvement in V ˙O2peak (15 ± 4 mL/kg/min vs. 17 ± 4; p = 0.001) and in work load (87 ± 30 watts vs. 108 ± 37; p = 0.001). Additionally, strength capacity significantly increased after the cardiac rehabilitation program, (quadriceps: 21 ± 18 kg vs. 29 ± 16 kg, p = 0.00003). Flexibility tests show a positive trend, but without statistical significance (sit-and-reach test: −19 ± 11 cm vs. −15 ± 11.7 cm; back-scratch test: −19 ± 11.6 cm vs. −15 ± 10 cm; lateral flexibility right −44 ± 1.4 cm vs. −43 ± 9.5 cm; left −43 ± 5 vs. −45 ± 8.7 cm). Conclusion: A brief period of combined aerobic, strength and flexibility exercise training (FIDE project) proved to be effective and safe in improving functional capacity in patients with cardiac implantable devices.

SCIENTIFIC PHYSICAL CORE STRENGTH TRAINING OF ADOLESCENT GROUP

ABSTRACT Introduction: A strong core can be more stable and improve the body posture of adolescents. This enables the organic integration and development of all parts of the body, as well as the coordination of the upper and lower limbs. Core strength training is conducive to improving its physical strength in the youth group. Objective: To study the influence of core strength on adolescents’ motor skills and physical literacy. Methods: 40 teenagers were selected for group training. The experimental group performed core strength training, while the control group used traditional strength training. After the training period, the improvement of the physical fitness and motor skills of the two groups of volunteers was analyzed. Results: There were statistical differences between the two groups of young athletes in various technical and physical fitness indicators. Conclusion: Core strength training can improve the basic skills of young athletes, such as fast running, jumping and so on, but the effect of improving high physical fitness is not obvious. The experiment shows that a certain period of core strength training can improve their physical and motor skills. In future training for youth, core strength training should be advocated. Level of evidence II; Evidence from well-designed randomized controlled trials.

The Effect of Different Periodization and Modes of Concurrent Strength and Endurance Training on Double Poling Performance and Body Composition in Adolescent Cross-Country Skiers.

The aim of the study was to compare the effects of different types and periodization of strength training on body composition and maximal aerobic performance in 10-week training period in adolescent XC skiers. Twenty-eight adolescent competitive cross-country skiers, including 10 females (age 17.9 ± 1.8 years; body mass 69.6 ± 9.7 kg; height 1.77 ± 0.1 m; training experience 8.6 ± 3.2 years) took part in this study. Pre-and post-intervention performance was measured with the incremental exercise test (Pmax) on a double poling ski ergometer. Changes in body composition were measured with DXA. In addition to regular endurance training, experimental group one (EXP1) performed maximal and explosive strength training two times per week, experimental group two (EXP2) performed maximal and explosive strength training 1–3 times per week, and the traditional (TRAD) group performed low intensity–high volume strength training 2 times per week. Increases in arm, trunk, and overall lean mass were found in TRAD (p < 0.05). Increases in arm lean-mass was found in EXP1 (p < 0.05), while no changes in body composition occurred in EXP2 (p ≥ 0.05). Pmax improved significantly in all groups (p < 0.05). Changes in body mass, overall and arm lean mass was related to changes in absolute performance (W; p < 0.05), while no relationships were found between changes in body composition parameters and relative performance (W/kg; p ≥ 0.05). In conclusion, different periodization of strength training led to similar improvements in double poling ergometer performance, but resulted in different changes in body composition (lean mass) in adolescent cross-country skiers.

Impacts of Androgen Abuse and Overtraining on Endocrine Profile in Bodybuilders

Abuse of androgens and overtraining expose bodybuilders to multifactorial stress influences related to endocrine activity. Endocrine responses in 23 bodybuilder athletes were investigated after a strength training period, during which they were taking high doses of androgenic-anabolic steroids. Serum concentrations of TSH, T3, and T4 were unchanged significantly. Serum LH and FSH concentrations decreased dramatically (P&lt;0.05). In addition, low mean concentration of serum testosterone was recorded, with more substantial reduction in participants of elder ages. The multiple regression model used in this analysis supported this inference. On the other hand, a positive association was observed between levels of blood lipids (total cholesterol, triglyceride) and the outcome predictor (mean serum testosterone level). The results also suggested a negative correlation between testosterone level and each of age and HDL level. The current study shows that excessive bodybuilding exercise has an impact on the hypothalamic–pituitary–thyroid (HPT) axis in top-level athletes. Also, simultaneous usage of anabolic steroids induces extreme shifts in the hypothalamic-pituitary–gonadal (HPGA) axis, which is reflected as changes in testosterone level, development of the overtraining syndrome, and adverse influences on hormonal control.

Asymmetry and changes in the neuromuscular profile of short-track athletes as a result of strength training

The purpose of this study was to identify the biomedical signals of short-track athletes by evaluating the effects of monthly strength training on changes in their neuromuscular profile, strength, and power parameters of the lower limb muscles. Muscle asymmetry, which can cause a risk of injury, was also evaluated. This study involved female athletes, age 18.8 ± 2.7 years, with a height of 162 ± 2.4 cm, and weight of 55.9 ± 3.9 kg. Before and after the monthly preparatory period prior to the season, strength measurements were assessed through the Swift SpeedMat platform, and reactivity of the lower limb muscles was assessed with tensiomyography (TMG). The athletes were also tested before and after the recovery training period. In the test after strength training, all average countermovement jump (CMJ) results improved. Flight time showed an increase with a moderate to large effect, using both legs (5.21%). Among the TMG parameters, time contraction (Tc) changed globally with a decrease (-5.20%). Changes in the results of the test after recovery training were most often not significant. A monthly period of strength training changes the neuromuscular profile of short-track female athletes, with no significant differences between the right and left lower limbs.

Influence of millimeter electromagnetic waves on the functional capabilities of the lower limb muscles in athletes - volleyball players

The authors, when observing 22 athletes - volleyball players of different volleyball specialization, assessed the effect of millimeter electromagnetic waves (EMW) on the functional state of the muscular system of the lower extremities. The electromagnetic effect was carried out using the "Complex SP 80" apparatus (frequencies 3900 - 4120 kHz were used). Electrodes were applied to the muscles of the thigh and lower leg, sinusoidal discharges were applied for 10 seconds during the strength training period. The results of observations showed that under the influence of EME, the height of the jump increases by 7%, due to the increase in the energy of the jump and its intensity. The release of the activity of the knee joint is also noted. The authors believe that under the influence of EME, the transmission of regulatory impulses in neuromuscular contact improves, which contributes to the synchronization and strength of contractions of the muscle fiber bundles. Also, under the influence of EMW, blood microcirculation in the muscle improves.

Effects of Different Periodization Models in Strength Training on Physical and Motor Skills during 24 Weeks of Training

Introduction: Periodization is the accurate manipulation of methodological variables of strength training (ST) to provide a progressive increase in the different manifestations of muscle strength. The most used models in ST are linear and undulatory periodization.&#x0D; Objective: Evaluate the effects of 24 weeks of training by applying three different models of ST periodization: Linear Periodization (LP), Weekly Undulating Periodization (WUP) and Daily Undulating Periodization (DUP) on: upper limb (UL) strength (submaximal and endurance), submaximal strength and power of the lower limbs (LL) and on other components of physical fitness (flexibility, agility and abdominal endurance strength).&#x0D; Methods: Experimental, longitudinal study, with a convenience sample, in which 29 people of both sexes participated, randomly allocated to the groups. Tests were performed pre- and post-intervention. ANOVA (two-way) of repeated measures was performed.&#x0D; Results: There was a significant increase in submaximal strength of the UL in the three periodization models: LP (p&lt;0.001), the WUP (p=0.002) and DUP (p=0.001). There was also a significant increase in submaximal strength of the LL with LP (p=0.002), WUP (p&lt;0.001) and with DUP (p=0.001). No significant intergroup differences were found in any test and time.&#x0D; Conclusion: In individuals without training experience, 24 weeks of TF provided gains in different manifestations of strength, regardless of the periodization model (LP, WUP or DUP). PL and WUP seem to be better at providing LL power gains in the horizontal jump.

Reliability, validity and responsiveness of pelvic floor muscle surface electromyography and manometry.

Vaginal surface electromyography (sEMG) is commonly used to assess pelvic floor muscle (PFM) function and dysfunction but there is a lack of studies regarding the assessment properties. The aim of the study was to test the hypotheses that sEMG has good test-retest intratester reliability, good criterion validity and is responsive to changes compared to manometry. PFM resting tone, maximum voluntary contraction (MVC) and endurance were measured in 66 women with pelvic floor dysfunction. One assessment by manometry was followed by two testing sessions with sEMG at baseline. After 4 to 42weeks of supervised PFM strength training, 29 participants were retested with both devices. Median age of the participants was 41years (range 24-83) and parity 2 (range 0-10). Very good test-retest intratester reliability was found for all three sEMG measurements. The correlation between sEMG and manometry was moderate for vaginal resting tone (r = 0.42, n= 66, p< 0.001) and strong for MVC (r = 0.66, n = 66, p < 0.001) and endurance (r = 0.67, n = 66, p < 0.001). Following the strength training period, participants demonstrated increased MVC and endurance measured with manometry, but not with sEMG. A significant reduction in resting tone was found only with sEMG. sEMG is reliable and correlates well with manometry. However, sEMG is not as responsive as manometry for changes in PFM MVC and endurance. For measurement of PFM resting tone, sEMG seems more responsive than manometry, but this requires further investigation.

Step vs. Two-Phase Gradual Volume Reduction Tapering Protocols in Strength Training: Effects on Neuromuscular Performance and Serum Hormone Concentrations.

Seppänen, S and Häkkinen, K. Step vs. two-phase gradual volume reduction tapering protocols in strength training: Effects on neuromuscular performance and serum hormone concentrations. J Strength Cond Res 36(10): 2771-2779, 2022-This study assessed effects of 2 reduced volume tapering protocols on neuromuscular performance and serum hormone concentrations in 14 recreationally strength-trained men (21-30 years). After an 8-week strength training period subjects were divided to the step (54% volume reduction immediately) and 2-phase gradual (38% reduction for the first week and 70% for the second week) tapering groups for 2 weeks. One repetition maximum (1RM) squat, maximal isometric bilateral leg press force (leg press MVIC), electromyography (EMG) of vastus lateralis (VL) and vastus medialis, cross-sectional area of VL, serum testosterone, cortisol, and sex hormone-binding globuline (SHBG) concentrations were measured before and repeatedly during training and tapering periods. Both tapering protocols led to significant increases ( p < 0.01) in squat 1RM. However, the increase in the step group (3.4 ± 2.1%) was higher ( p < 0.05) than in the gradual group (1.7 ± 0.9%). The maximal integrated EMG of VL increased ( p < 0.05) during tapering in the step group. Serum testosterone concentration increased ( p < 0.05) and T/SHBG ratio reached the highest level after 1-week tapering in the step group. In the gradual group, T/SHBG ratio was ( p < 0.05) higher after the taper than after the training period. Individual changes in T/SHBG ratio in the total group correlated positively ( p < 0.05) with individual changes in leg press MVIC during the taper. These results suggest that reducing training volume can be an effective way to peak maximal strength. However, a higher volume reduction rate at the beginning of taper seems to lead to more favorable changes in maximal strength accompanied by positive changes in the neuromuscular system and serum hormone concentrations when taper follows an overreaching period.

Impact of exercise training and supplemental oxygen on submaximal exercise performance in patients with COPD.

Functional impairment caused by chronic obstructive pulmonary disease (COPD) impacts on activities of daily living and quality of life. Indeed, patients’ submaximal exercise capacity is of crucial importance. It was the aim of this study to investigate the effects of an exercise training intervention with and without supplemental oxygen on submaximal exercise performance. This is a secondary analysis of a randomized, controlled, double‐blind, crossover trial. 29 COPD patients (63.5 ± 5.9 years; FEV1 46.4 ± 8.6%) completed two consecutive 6‐week periods of high‐intensity interval cycling and strength training, which was performed three times/week with either supplemental oxygen or medical air (10 L/min). Submaximal exercise capacity as well as the cardiocirculatory, ventilatory, and metabolic response were evaluated at isotime (point of termination in the shortest cardiopulmonary exercise test), at physical work capacity at 110 bpm of heart rate (PWC 110), at the anaerobic threshold (AT), and at the lactate‐2 mmol/L threshold. After 12 weeks of exercise training, patients improved in exercise tolerance, shown by decreased cardiocirculatory (heart rate, blood pressure) and metabolic (respiratory exchange ratio, lactate) effort at isotime; ventilatory response was not affected. Submaximal exercise capacity was improved at PWC 110, AT and the lactate‐2 mmol/L threshold, respectively. Although supplemental oxygen seems to affect patients’ work rate at AT and the lactate‐2 mmol/L threshold, no other significant effects were found. The improved submaximal exercise capacity and tolerance might counteract patients’ functional impairment. Although cardiovascular and metabolic training adaptations were shown, ventilatory efficiency remained essentially unchanged. The impact of supplemental oxygen seems less important on submaximal training effects.

Effects of acute and chronic strength training on skeletal muscle autophagy in frail elderly men and women.

Aging is associated with alterations in skeletal muscle autophagy, potentially affecting both muscle mass and quality in a negative manner. Strength training with protein supplementation has been reported to improve both muscle mass and quality in frail elderly individuals, but whether improvements are accompanied by alterations in protein quality control is not known. To address this issue, we investigated protein degradation markers in skeletal muscle biopsies (m. vastus lateralis) from twenty-four frail elderly men and women (86±7yr) after acute and chronic (10weeks) strength training with protein supplementation (ST+PRO) or protein supplementation alone (PRO). Acute increases in mRNA expression of genes related to the ubiquitin proteasome system (MuRF-1, MUSA1), autophagy (ATG7, LC3, p62), and mitochondrial fission (DRP1) were observed after the first, but not after the last training session in ST+PRO. Acute changes in gene expression were accompanied by changes in protein levels of both LC3-I and LC3-II. Hence, the acute training-induced activation of proteasomal degradation and autophagy seems to depend on training status, with activation in the untrained, but not trained state. The ten-week training intervention did not affect basal levels of autophagy mRNAs and proteins, and neither markers of the ubiquitin-proteasome system. This suggests that a relatively short period of strength training may not be sufficient to increase the basal rate of protein degradation in frail elderly.

The Flywheel Paradigm in Team Sports: A Soccer Approach

ABSTRACT Strength training is a key strategy to improve performance and injury prevention in team sports. Accordingly, several methods have been used, although because of the benefits reported after training based on eccentric contractions, the use of flywheel (FW) devices has extended within the periodization of strength training of team sports. However, nowadays, there is no clear consensus about the parameters used to optimize the training effects. This article examines the research behind these claims and attempts to draw evidence-based conclusions as to the practical implications for a precise use of FW with team-sport players, attending to their specific demands and objectives.

A NECK STRENGTH TRAINING PROTOCOL IN HIGH SCHOOL FOOTBALL PLAYERS FOR CONCUSSION RISK REDUCTION

Background:Increased neck strength may be a protective factor for reducing concussions in youth athletes. However, little research exists regarding validated neck strength training methods among this demographic.Purpose:To determine whether a 7-week neck strength training period is sufficient to achieve significant gains in neck strength and size amongst high school football players. Additionally, to assess if increased neck strength influences concussion outcomes.Methods:This study enrolled 54 male high school football players, ages 14-17, in a 7-week strength training protocol in which neck exercises were incorporated into preseason strength and conditioning workouts (figure 1). Pre- and post-neck strength was assessed in four directions: forward flexion (FF), extension (EXT), right lateral flexion (RLF) and left lateral flexion (LLF). Strength was measured as maximal isometric head pressure applied into a pre-inflated sphygmomanometer cuff (figure 2). Concussion totals from the subsequent 2018 season were compared with totals from the 2017 and 2016 seasons per data obtained from the team’s athletic trainer.Results:Fifty athletes in total were analyzed; 4/54 athletes did not complete final testing due to scheduling conflicts. A two sample t-test of neck circumferences revealed a statistically significant increase of 0.37 cm from pre- to post-neck strength training (p=0.0025, figure 3). Single sample strength t-test analysis (corrected for cuff pre-inflation) demonstrated a statistically significant post-test strength increase of 19.8% (FF), 11.0% (EX), 18.8% (RLF), and 18.0% (LLF) (p<0.001, figure 3). The team suffered 4 concussions in the 2018 season, 2 of which were sustained by athletes who did not participate in preseason neck training, compared to 12 concussions in 2017 and 7 concussions in 2016 (figure 3).ConclusionThis study demonstrates that increases in neck size and strength can be achieved amongst high school athletes using easily implemented training methods during a 7-week preseason training period. The additional observation of reduced concussion outcomes is not conclusive, though these initial results are promising. Additional research is needed to investigate the potential of neck strengthening in modifying concussion risk. Funding provided by the Stanford Medical Scholars Fellowship Program Figure 1.Neck ExercisesFigure 2.Strength TestingFigure 3.Results

Strength-Training Periodization: No Effect on Swimming Performance in Well-Trained Adolescent Swimmers.

To assess the effects of periodized versus nonperiodized dry-land strength training (DLST) on indices of swimming performance in well-trained adolescent swimmers. Sixteen athletes (10 boys and 6 girls; age 14.9 [1.1]y) performed similar endurance training for 16 weeks (29.1 [7.5]km·wk-1). During weeks 1 to 7, all athletes additionally performed 2 or 3 times weekly whole-body DLST (3 × 6-10 repetitions at 75-85% 1-repetition maximum[1RM]). Thereafter, the DLST frequency was maintained, but athletes were stratified into periodized (experimental, n = 9) and nonperiodized (control, n = 7) DLST groups. The experimental group performed maximal (3 × 3-4 repetitions at 85-90% 1RM) and explosive DLST (throws and unloaded jumps), while in the control group, DLST was maintained. Swimming time at 4mmol·L-1 of blood lactate improved after 7weeks in both the experimental (+2.6% [1.8%], P = .033) and the control groups (+3.2% [2.4%], P = .081) and plateaued thereafter. Ten-meter start improved in both the experimental (-3.6% [2.5%], P = .039) and the control groups (-5.1% [2.2%], P = .054) throughout the entire intervention. Both groups improved in maximal weight lifted in half-squat (experimental, +19.6% [14.9%], P = .021; control, +25.7% [18.4%], P = .054) and bench press (experimental, +14.1% [4.8%], P = .018; control, +19.3% [11.1%], P = .051). Countermovement-jump height increased only in the experimental group throughout the intervention (+19.4% [7.0%], P = .024). The associations for the pooled changes in half-squat performance and 4mmol·L-1 of blood lactate were statistically significant (r = .560, P = .024). The findings do not support the superior effects of DLST periodization in adolescent swimmers. However, the association between improvements in lower-body strength and swimming performance still indicates the importance of muscle strength in this age group.

Developing Powerful Athletes, Part 1: Mechanical Underpinnings

ABSTRACT This review will revisit practitioner understanding of the development of power, before outlining some of the key mechanical parameters that contribute to power development. This understanding will help with planning and periodization of strength and power training, which is explored in part 2 of this 2-part review. This review (part 1) discusses the force-time and force-velocity curve and addresses recent criticism in using terms such as power, rate of force development, and explosiveness, over impulse. These terms are distinguished mechanically and conceptually for the benefit of the scientist and coach, and are essential for effective sharing of data and practice.

Linear periodization of strength training in blocks attenuates hypertension and diastolic dysfunction with normalization of myocardial collagen content in spontaneously hypertensive rats.

This study evaluated the effects of a linear block strength training programme on the parameters of cardiac remodelling in spontaneously hypertensive rats. Thirty-nine rats were equally distributed in four groups: normotensive sedentary, normotensive trained, hypertensive sedentary and hypertensive trained. The strength training protocol was organized in three mesocycles of 4 weeks, with an increase in the training load organized in a linear fashion for each block, considering the weight established in the maximum loaded load test. The following parameters were evaluated: ventricular function assessed by echocardiogram, caudal blood pressure, ventricular haemodynamics and cardiac masses. Two-way analysis of variance was used to determine the differences between the group and time. After 12 weeks of training, the hypertensive trained group presented the following results: increased muscle strength, reduced blood pressure, reduced heart rate, isovolumetric relaxation time and total collagen content, with increased cardiac function, without promoting changes in the mass and nuclear volume of cardiomyocytes. Also, blood pressure reduction seems to be associated with both muscle strength adjustments and total load progress. The findings of this study showed that the training programme carried out attenuated systemic arterial pressure and preserved the ventricular function of spontaneously hypertensive rats without cardiac mass change.