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Background: Few mobile health resistance-based physical activity interventions have targeted community-dwelling adults. "Ecofit" is a multicomponent intervention that promotes resistance and aerobic activities using smartphone technology, outdoor gyms, and social support. This study evaluated process evaluation outcomes of the ecofit randomized controlled trial: (1) the acceptability and usability of the ecofit smartphone app and app user workouts; (2) perceptions of factors influencing outdoor gym use; and (3) the fidelity, reach, recruitment, and dose received of the ecofit program., Methods: Process data were collected through program evaluation surveys at 3 months, and app usage data were collected via the intervention platform for up to 3 months. Data were analyzed using descriptive statistics., Results: The survey was completed by 57% (n = 69) of eligible participants. The majority (93%) believed the app provided them with sufficient information to perform muscle-strengthening activities. Approximately half (51%) agreed that the goal-setting function encouraged them to complete their workouts, and 42% agreed that the self-assessment helped them monitor progress. "Proximity" to outdoor gyms emerged as the most important factor for choosing locations to workout (mean = 5.5, SD = 1.1). Participants logged a median of 5.5 (interquartile range = 19) workouts and 1 (interquartile range = 1) upper- and lower-body muscular fitness self-assessment., Conclusions: The ecofit app provided participants with sufficient skills to perform unsupervised resistance training exercises using mobile health. Only half of the participants regarded self-assessments and goal setting as useful, suggesting a need for modifications to how these are implemented. Mobile health remains a promising delivery platform to promote unsupervised resistance training, although more research is needed to improve uptake.

Introduction: In Australia, only 22% of male and 8% of female adolescents meet the muscle-strengthening physical activity guidelines, and few school-based interventions support participation in resistance training (RT). After promising findings from our effectiveness trial, we conducted a state-wide dissemination of the ' Resistance Training for Teens ' (RT4T) intervention from 2015 to 2020. Despite high estimated reach, we found considerable variability in programme delivery and teachers reported numerous barriers to implementation. Supporting schools when they first adopt evidence-based programmes may strengthen programme fidelity, sustainability, and by extension, programme impact. However, the most effective implementation support model for RT4T is unclear., Objective: To compare the effects of three implementation support models on the reach (primary outcome), dose delivered, fidelity, sustainability, impact and cost of RT4T., Methods and Analysis: We will conduct a hybrid type III implementation-effectiveness trial involving grade 9 and 10 (aged 14-16 years) students from 90 secondary schools in New South Wales (NSW), Australia. Schools will be recruited across one cohort in 2023, stratified by school type, socioeconomic status and location, and randomised in a 1:1:1 ratio to receive one of the following levels of implementation support: (1) 'low' (training and resources), (2) 'moderate' (training and resources+external support) or 'high' (training and resources+external support+equipment). Training includes a teacher workshop related to RT4T programme content (theory and practical sessions) and the related resources. Additional support will be provided by trained project officers from five local health districts. Equipment will consist of a pack of semiportable RT equipment (ie, weighted bars, dumbbells, resistance bands and inverted pull up bar stands) valued at ~$A1000 per school. Study outcomes will be assessed at baseline (T0), 6 months (T1) and 18 months (T2). A range of quantitative (teacher logs, observations and teacher surveys) and qualitative (semistructured interviews with teachers) methods will be used to assess primary (reach) and secondary outcomes (dose delivered, fidelity, sustainability, impact and cost of RT4T). Quantitative analyses will use logistic mixed models for dichotomous outcomes, and ordinal or linear mixed effects regression models for continuous outcomes, with alpha levels set at p<0.025 for the outcomes and cost comparisons of the moderate and high support arms against the low support arm., Ethics and Dissemination: Ethics approval has been obtained from the University of Newcastle (H-2021-0418), the NSW Department of Education (SERAP:2022215), Hunter New England Human Research Ethics Committee (2023/ETH00052) and the Catholic Schools Office. The design, conduct and reporting will adhere to the Consolidated Standards of Reporting Trials statement, the Standards for Reporting Implementation Studies statement and the Template for Intervention Description and Replication checklist. Findings will be published in open access peer-reviewed journals, key stakeholders will be provided with a detailed report. We will support ongoing dissemination of RT4T in Australian schools via professional learning for teachers., Trial Registration Number: ACTRN12622000861752., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY. Published by BMJ.)

Importance: Childhood obesity is a risk factor associated with type 2 diabetes, cardiovascular disease, and mental disorders later in life. Investigation of the parallel effects of a defined exercise program on cardiometabolic and mental health in children with overweight or obesity may provide new insights on the potential benefits of exercise on overall health., Objective: To investigate the effects of a 20-week exercise program on cardiometabolic and mental health in children with overweight or obesity., Design, Setting, and Participants: This secondary analysis of a parallel-group randomized clinical trial was conducted in Granada, Spain, from November 1, 2014, to June 30, 2016. Data analyses were performed between February 1, 2020, and July 14, 2022. Children with overweight or obesity aged 8 to 11 years were eligible, and the study was performed in an out-of-school context., Intervention: The exercise program included 3 to 5 sessions/wk (90 min/session) of aerobic plus resistance training for 20 weeks. The wait-list control group continued with their usual routines., Main Outcomes and Measures: Cardiometabolic outcomes as specified in the trial protocol included body composition (fat mass, fat-free mass, and visceral adipose tissue), physical fitness (cardiorespiratory, speed-agility, and muscular), and traditional risk factors (waist circumference, blood lipid levels, glucose levels, insulin levels, and blood pressure). Cardiometabolic risk score (z score) was calculated based on age and sex reference values for levels of triglycerides, inverted high-density lipoprotein cholesterol, and glucose, the mean of systolic and diastolic blood pressure, and waist circumference. An additional cardiometabolic risk score also included cardiorespiratory fitness. Mental health outcomes included an array of psychological well-being and ill-being indicators., Results: The 92 participants included in the per-protocol analyses (36 girls [39%] and 56 boys [61%]) had a mean (SD) age of 10.0 (1.1) years. The exercise program reduced the cardiometabolic risk score by approximately 0.38 (95% CI, -0.74 to -0.02) SDs; decreased low-density lipoprotein cholesterol level by -7.00 (95% CI, -14.27 to 0.37) mg/dL (to convert to mmol/L, multiply by 0.0259), body mass index (calculated as weight in kilograms divided by height in meters squared) by -0.59 (95% CI, -1.06 to -0.12), fat mass index by -0.67 (95% CI, -1.01 to -0.33), and visceral adipose tissue by -31.44 (95% CI, -58.99 to -3.90) g; and improved cardiorespiratory fitness by 2.75 (95% CI, 0.22-5.28) laps in the exercise group compared with the control group. No effects were observed on mental health outcomes., Conclusions and Relevance: In this secondary analysis of a randomized clinical trial, an aerobic plus resistance exercise program improved cardiometabolic health in children with overweight or obesity but had no effect on mental health., Trial Registration: ClinicalTrials.gov Identifier: NCT02295072.

Introduction: In Australia, 45% of adults meet the aerobic recommendations, and only 9%-30% meet the resistance training guidelines. Given the lack of at-scale community-based interventions promoting resistance training, the aim of this study was to assess the impact of an innovative mHealth intervention on upper- and lower-body muscular fitness, cardiorespiratory fitness, physical activity, and social-cognitive mediators among a sample of community-dwelling adults., Study Design: Researchers evaluated the community-based ecofit intervention using a cluster RCT from September 2019 to March 2022 in 2 regional municipalities of New South Wales, Australia., Setting/participants: Researchers recruited a sample of 245 participants (72% female, aged 53.4±13.9 years) who were randomized to the ecofit intervention group (n=122) or waitlist control (n=123) group., Intervention: The intervention group received access to a smartphone application with standardized workouts tailored to 12 outdoor gym locations and an introductory session. Participants were encouraged to perform at least 2 ecofit workouts per week., Main Outcome Measures: Primary and secondary outcomes were assessed at baseline, 3 months, and 9 months. The coprimary muscular fitness outcomes were evaluated using the 90-degree push-up and the 60-second sit-to-stand test. Intervention effects were estimated using linear mixed models accounting for group-level clustering (participants could enroll in groups of up to 4). Statistical analysis was conducted in April 2022., Results: Statistically significant improvements were observed in upper (1.4 repetitions, 95% CI=0.3, 2.6, p=0.018) and lower (2.6 repetitions, 95% CI=0.4, 4.8, p=0.020) body muscular fitness at 9 months but not at 3 months. Increases in self-reported resistance training, resistance training self-efficacy, and implementation intention for resistance training were statistically significant at 3 and 9 months., Conclusions: This study has shown that a mHealth intervention promoting resistance training using the built environment can improve muscular fitness, physical activity behavior, and related cognitions in a community sample of adults., Trial Registration: This trial was preregistered with the Australian and New Zealand Clinical Trial Registry (ACTRN12619000868189)., (Copyright © 2023 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.)

Type 2 diabetes mellitus (T2DM) accounts for approximately 90% of diabetes cases globally. Regular physical activity is regarded as one of the key components in T2DM management. Aerobic exercise was traditionally recommended; however, there is a growing body of research examining the independent effect of resistance training (RT) on glycemic control. This systematic review and meta-analysis aimed to conduct an update on the effects of RT on glycosylated hemoglobin (HbA1c) in adults with T2DM and examine the moderating effects of training effect (ie, muscular strength improvements), risk of bias and intervention duration. Peer-reviewed articles published in English were searched across MEDLINE, Embase, CINAHL, Scopus and SPORTDiscus from database inception until January 19, 2021. Each online database was systematically searched for randomized controlled trials reporting on the effects of RT on HbA1c in individuals with T2DM. Twenty studies (n=1172) were included in the meta-analysis. RT significantly reduced HbA1c compared with controls (weighted mean difference=-0.39, 95% CI -0.60 to -0.18, p<0.001, I 2 =69.20). Training effect significantly (p<0.05) moderated the results, with larger improvements in muscular strength leading to greater reductions in HbA1c (β=-0.99, CI -1.97 to -0.01). Intervention duration and risk of bias did not significantly moderate the effects. As a secondary analysis, this study found no significant differences in HbA1c when comparing RT and aerobic training (p=0.42). This study demonstrates that RT is an effective strategy to decrease HbA1c in individuals with T2DM. Importantly, RT interventions that had a larger training effect appeared more effective in reducing HbA1c, compared with interventions producing medium and small effects. PROSPERO registration number CRD42020134046., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Physical activity guidelines recommend young people engage in regular muscle-strengthening activities (e.g., resistance training [RT]). However, few school-based physical activity interventions have been delivered at-scale or promoted RT. The aim of this study was to evaluate the reach, effectiveness, adoption, implementation and maintenance of the Resistance Training for Teens (RT for Teens) program., Methods: Data were collected between August 2015 and October 2020. RE-AIM was operationalized as: (i) Reach: number and characteristics of students estimated to be exposed to the program; (ii) Effectiveness: impact of the program on student-level outcomes measured in a subsample of 750 students from 17 schools; (iii) Adoption: number and representativeness of schools with one or more teachers trained to deliver the program; (iv) Implementation: extent to which the program was delivered as intended; and (v) Maintenance: extent to which the program was sustained in schools., Results: The estimated program reach was ~ 10,000 students, out of a total student population of ~ 200,000 (~ 5%). Students were from diverse socioeconomic and ethnic backgrounds. Improvements in muscular fitness, RT self-efficacy, perceived cardiorespiratory fitness and flexibility, and participation in muscle-strengthening physical activities were documented. A total of 30 workshops were delivered, involving 468 teachers from 249 schools from diverse geographical regions. Implementation varied considerably, with teachers adapting the program to suit the context of their school and student cohorts. However, RT skill development and the promotion of muscular fitness were the session components delivered most during sessions. Teachers' adherence to the SAAFE (Supportive, Active, Autonomous, Fair and Enjoyable) teaching principles was high. Approximately 30% of teachers (144/476) registered to use the RT for Teens app. At the school-level, 37% (93/249) of schools had at least one registered user (teacher and/or student). A total of 2,336 workouts and 3,116 fitness tests were completed by registered users. Of the 249 schools represented, 51 (20.5%) sent an additional (previously untrained) teacher to a second workshop., Conclusions: The RT for Teens program had broad reach and adoption. However, intervention delivery varied considerably across schools and additional support strategies are required to optimize intervention implementation and maintain program delivery over time. Future studies will benefit from the utilization of accepted frameworks, recommendations and guidelines for implementation research., Trial Registration: Australian New Zealand Clinical Trials Registry (ACTRN12621000352808), retrospectively registered 1 st February 2021., (© 2021. The Author(s).)

Harries, SK, Lubans, DR, Buxton, A, MacDougall, THJ, and Callister, R. Effects of 12-week resistance training on sprint and jump performances in competitive adolescent rugby union players. J Strength Cond Res 32(10): 2762-2769, 2018-Sprint performance is an important characteristic for success in many sports, including rugby union. Resistance training is used to increase muscular fitness (i.e., strength, endurance, and power) and may also be effective for improving sprint and jump performances. The aims of this study were to examine the effects of resistance training using 2 different periodized programs (linear and daily undulating) on sprint and jump performances and explore relationships between performance measures. Sixteen male (16.9 ± 1.0 years) adolescent rugby union players participated in 12 weeks of resistance training. A further 10 male (15.5 ± 1.0 years) participants were recruited as a control group. Assessments of strength (box squat), 10- and 20-m sprint (electronically timed), and jump height (maximal unloaded (body mass only) and loaded (body mass + 10 kg) countermovement jumps) were conducted before and after 12 weeks training. Large to very large increases in 1 repetition maximum box squat (linear: 33.9%; p < 0.001; effect size (ES) = 1.64; daily undulating: 44.5%; p < 0.001; ES = 2.33) were observed after training. Small decreases were seen in 10-m (linear: -1.6%; p = 0.171; ES = -0.84; daily undulating: -2.5%; p = 0.038; ES = -0.36) and 20-m (linear: -0.5%; p = 0.506; ES = -0.20; daily undulating: -1.7%; p = 0.047; ES = -0.27) sprint times. Small-to-moderate associations between changes in lower-body strength and improvements in 10- and 20-m sprint times were found. Resistance training increases lower-body strength in adolescent rugby union players and increases in lower-body strength may transfer to improved sprinting performance with improvements after daily undulating periodized resistance training slightly superior.

The aim of this study is to examine the prevalence and correlates of adolescents' resistance training (RT) skill competence. Participants were 548 adolescents (14.1 ± 0.5 years) from 16 schools in New South Wales, Australia. RT skills were assessed using the Resistance Training Skills Battery. Demographics, BMI, muscular fitness, perceived strength, RT self-efficacy, and motivation for RT were also assessed. The proportion demonstrating "competence" and "near competence" in each of the six RT skills were calculated and sex differences explored. Associations between the combined RT skill score and potential correlates were examined using multi-level linear mixed models. Overall, the prevalence of competence was low (range = 3.3% to 27.9%). Females outperformed males on the squat, lunge and overhead press, whereas males performed better on the push-up (p < .05). Significant associations were seen for a number of correlates, which largely differed by sex. Muscular fitness was moderately and positively associated with RT skills among both males (β = 0.34, 95%CIs = 0.23 to 0.46) and females (β = 0.36, 95%CIs = 0.23 to 0.48). Our findings support a link between RT skills and muscular fitness. Other associations were statistically significant but small in magnitude, and should therefore be interpreted cautiously.

Purpose: Guidelines recommend that young people engage in muscle-strengthening activities on at least 3 d·wk. The purpose of this study was to examine the effect of a school-based intervention focused on resistance training (RT) for adolescents., Methods: The "Resistance Training for Teens" intervention was evaluated using a cluster-randomized, controlled trial with 607 adolescents (50.1% girls; 14.1 ± 0.5 yr) from 16 secondary schools. Teachers were trained to deliver the intervention, which included the following: (i) an interactive student seminar; (ii) a structured physical activity program, focused on RT; (iii) lunchtime fitness sessions; and (iv) Web-based smartphone apps. The primary outcome was muscular fitness (MF) and secondary outcomes included body mass index, RT skill competency, flexibility, physical activity, self-efficacy, and motivation. Assessments were conducted at baseline, 6 months (postprogram; primary end point), and 12 months (follow-up). Outcomes were assessed using linear mixed models, with three potential moderators tested using interaction terms (and subgroup analyses where appropriate)., Results: For the primary outcome (MF), a group-time effect was observed at 6 months for the upper body (2.0 repetitions; 95% confidence interval (CI), 0.8-3.2), but not the lower body (-1.4 cm; 95% CI, -4.7-1.9). At 6 months, there were intervention effects for RT skill competency and self-efficacy, but no other secondary outcomes. Effects for upper body MF and RT skill competency were sustained at 12 months. Despite overall no effect for body mass index, there was a group-time effect at 12 months among students who were overweight/obese at baseline (-0.55 kg·m; 95% CI, -1.01 to -0.08)., Conclusions: The school-based RT intervention resulted in immediate and sustained improvements in upper body MF and RT skill competency, demonstrating an effective and scalable approach to delivering RT within secondary schools.

Objective: Regular participation in resistance training (RT) is critical to health and recommended in most international physical activity guidelines. Few people, however, participate in RT. The purpose of this review was to assess the demographic, behavioural, intrapersonal, interpersonal and environmental factors associated with participating in RT., Data Sources: Eligible studies were from English peer-reviewed published articles that examined correlates or determinants of RT in adult samples. Searches were performed from August 2015 to April 2016 in six databases., Results: We identified 51 independent data sets, from nine countries, primarily of moderate to high quality, and 23 factors related to participating in RT. Education, perceived health status, quality of life, affective judgements, self-efficacy, intention, self-regulation behaviours, subjective norm and programme leadership were associated with RT., Conclusion: Low education levels and poor health status were associated with low participation rates in RT. Intrapersonal factors including affective judgements, self-efficacy, and self-regulation behaviours, and interpersonal factors including subjective norms and programme leadership may be important for promoting RT behaviours., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Harris, NK, Dulson, DK, Logan, GRM, Warbrick, IB, Merien, FLR, and Lubans, DR. Acute responses to resistance and high-intensity interval training in early adolescents. J Strength Cond Res 31(5): 1177-1186, 2017-The purpose of this study was to compare the acute physiological responses within and between resistance training (RT) and high-intensity interval training (HIIT) matched for time and with comparable effort, in a school setting. Seventeen early adolescents (12.9 ± 0.3 years) performed both RT (2-5 repetitions perceived short of failure at the end of each set) and HIIT (90% of age-predicted maximum heart rate), equated for total work set and recovery period durations comprising of 12 "sets" of 30-second work followed by 30-second recovery (total session time 12 minutes). Variables of interest included oxygen consumption, set and session heart rate (HR), and rate of perceived exertion, and change in salivary cortisol (SC), salivary alpha amylase, and blood lactate (BL) from presession to postsession. Analyses were conducted to determine responses within and between the 2 different protocols. For both RT and HIIT, there were very large increases pretrial to posttrial for SC and BL, and only BL increased greater in HIIT (9.1 ± 2.6 mmol·L) than RT (6.8 ± 3.3 mmol·L). Mean set HR for both RT (170 ± 9.1 b·min) and HIIT (179 ± 5.6 b·min) was at least 85% of HRmax. V[Combining Dot Above]O2 over all 12 sets was greater for HIIT (33.8 ± 5.21 ml·kg·min) than RT (24.9 ± 3.23 ml·kg·min). Brief, repetitive, intermittent forays into high but not supramaximal intensity exercise using RT or HIIT seemed to be a potent physiological stimulus in adolescents.

Background: The purpose of this study was to experimentally examine the extent to which variety support in a resistance exercise program influences exercise-related well-being among inactive adults., Methods: A sample of 121 inactive university students were randomly assigned and participated in either a high or low variety support 6-week exercise program. Measures of exercise-related perceived variety, positive affect, negative affect, and subjective vitality were completed at baseline, after 3 weeks, and after 6 weeks (i.e. post-test)., Results: Through use of structural equation modelling, the results showed that for those who completed measures at post-test (i.e. n = 55), and for all participants who received variety support (i.e. a modified intention-to-treat analysis; N = 121), exercise-related variety support indirectly explained higher levels of exercise-related positive affect, and subjective vitality, and lower levels of negative affect, through the mediating role of perceived variety., Conclusions: The provision of variety support in a resistance exercise program influences exercise-related well-being through perceptions of variety. Results are discussed in relation to the potential utility of providing variety support to promote exercise-related well-being in people who are physically inactive., (© 2016 The International Association of Applied Psychology.)

Objectives: To determine changes in maximal strength between two different resistance training progression models, linear (LP) and daily undulating (DUP), over a 12-week resistance training programme in sub-elite adolescent rugby union players., Design: The study used a quasi-experimental study design. Following baseline assessments, participants from Squad 1 were randomised to either LP or DUP; participants from Squad 2 formed a non-randomised comparison group (CON)., Methods: Participants were 26 sub-elite adolescent rugby union players who were assessed at baseline and after 12 weeks. Outcomes included 5 repetition maximum (RM) box squat and bench press, height, body weight, skeletal muscle mass, percentage body fat and maturation status., Results: Participants in both the LP and DUP groups significantly increased their squat and bench press strength from baseline to 12 weeks. There were no significant differences between groups for squat and bench press increases after 12 weeks (p>0.05). No significant increases in squat or bench press strength were observed after 12 weeks in the CON group. Increases in lower body strength were large in the LP group (ES: 1.64) and very large in the DUP group (ES: 2.33). Upper body strength changes were small in both groups (LP, ES: 0.57; DUP, ES: 0.31)., Conclusions: Twelve weeks of LP or DUP resistance training are both effective at increasing maximal lower and upper body strength in adolescent rugby athletes. Additionally, twice weekly frequency of resistance training in adolescent rugby athletes with greater than 6-months resistance training experience is sufficient to elicit substantial increases in maximal strength., (Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

The purpose of this study was to examine the mediating effect of resistance training skill competency on percentage of body fat, muscular fitness and physical activity among a sample of adolescent boys participating in a school-based obesity prevention intervention. Participants were 361 adolescent boys taking part in the Active Teen Leaders Avoiding Screen-time (ATLAS) cluster randomised controlled trial: a school-based program targeting the health behaviours of economically disadvantaged adolescent males considered "at-risk" of obesity. Body fat percentage (bioelectrical impedance), muscular fitness (hand grip dynamometry and push-ups), physical activity (accelerometry) and resistance training skill competency were assessed at baseline and post-intervention (i.e., 8 months). Three separate multi-level mediation models were analysed to investigate the potential mediating effects of resistance training skill competency on each of the study outcomes using a product-of-coefficients test. Analyses followed the intention-to-treat principle. The intervention had a significant impact on the resistance training skill competency of the boys, and improvements in skill competency significantly mediated the effect of the intervention on percentage of body fat and the combined muscular fitness score. No significant mediated effects were found for physical activity. Improving resistance training skill competency may be an effective strategy for achieving improvements in body composition and muscular fitness in adolescent boys.

The aim of this study was to evaluate the preliminary efficacy and feasibility of the CrossFit Teens™ resistance training programme for improving health-related fitness and resistance training skill competency in adolescents. This assessor-blinded randomised controlled trial was conducted in one secondary school in the Hunter Region, Australia, from July to September 2013. Ninety-six (96) students (age = 15.4 (.5) years, 51.5% female) were randomised into intervention (n = 51) or control (n = 45) conditions for 8-weeks (60 min twice per week). Waist circumference, body mass index (BMI), BMI-Z score (primary outcomes), cardiorespiratory fitness (shuttle run test), muscular fitness (standing jump, push-up, handgrip, curl-up test), flexibility (sit and reach) and resistance training skill competency were measured at baseline and immediate post-intervention. Feasibility measures of recruitment, retention, adherence and satisfaction were assessed. Significant group-by-time intervention effects were found for waist circumference [-3.1 cm, P < 0.001], BMI [-1.38 kg · m(‒)(2), P < 0.001], BMI-Z [-0.5 z-scores, P < 0.001], sit and reach [+3.0 cm, P < 0.001], standing jump [+0.1 m, P = 0.021] and shuttle run [+10.3 laps, P = 0.019]. Retention rate was 82.3%. All programme sessions were delivered and participants' mean satisfaction scores ranged from 4.2 to 4.6 out of 5. The findings demonstrate that CrossFit Teens™ is a feasible and efficacious programme for improving health-related fitness in adolescents.

Periodization is known to improve training adaptations but the most effective periodization approach for muscular strength development for a wide variety of populations is yet to be determined. This systematic review and meta-analysis examined all studies directly comparing linear and undulating periodized resistance training programs to determine and compare their effects on muscular strength. A systematic search of the MEDLINE, SCOPUS, and SPORTDiscus databases revealed 17 studies satisfying the inclusion criteria. There were a total of 510 participants in the included studies. Sixteen studies reported significant increases in strength for both periodization approaches. Five studies reported significant differences in improvements between groups. The meta-analyses determined that there were no differences in the effectiveness of linear vs. undulating periodization on upper-body or lower-body strength. The short-term nature of studies and the previous training history of participants were identified as potential confounding factors in the interpretation of findings. The results suggest that novelty or training variety are important for stimulating further strength development. Few studies have examined the effect of periodization approaches in adolescent or athletic populations.

Objectives: The study aim was to assess rater agreement of the Resistance Training Skills Battery (RTSB) for adolescents. The RTSB provides an assessment of resistance training skill competency and includes six exercises. The RTSB can be used to assess performance and progress in adolescent resistance training programmes and to provide associated feedback to participants. Individual skill scores are based on the number of performance criteria successfully demonstrated and an overall resistance training skill quotient (RTSQ) is created by summing the six skill scores., Design/methods: The eight raters had varying experience in movement skill assessment and resistance training and completed a 2-3h training session in how to assess resistance training performance using the RTSB. The raters then completed an assessment on six skills for 12 adolescents (mean age=15.1 years, SD=1.0, six male and six female) in a randomised order., Results: Agreement between seven of the eight raters was high (20 of the 21 pairwise correlations were greater than 0.7 and 13 of the 21 were greater than 0.8). Correlations between the eighth rater and each of the other seven raters were generally lower (0.45-0.78). Most variation in the assigned RTSB scores (67%) was between cases, a relatively small amount of the variation (10%) was between raters and the remainder (23%) was between periods within raters. The between-raters coefficient of variation was approximately 5%., Conclusions: The RTSB can be used reliably by those with experience in movement skill assessment and resistance training to assess the resistance skill of adolescents., (Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

The aim of this study was to describe the development and assess test-retest reliability and construct validity of the Resistance Training Skills Battery (RTSB) for adolescents. The RTSB provides an assessment of resistance training skill competency and includes 6 exercises (i.e., body weight squat, push-up, lunge, suspended row, standing overhead press, and front support with chest touches). Scoring for each skill is based on the number of performance criteria successfully demonstrated. An overall resistance training skill quotient (RTSQ) is created by adding participants' scores for the 6 skills. Participants (44 boys and 19 girls, mean age = 14.5 ± 1.2 years) completed the RTSB on 2 occasions separated by 7 days. Participants also completed the following fitness tests, which were used to create a muscular fitness score (MFS): handgrip strength, timed push-up, and standing long jump tests. Intraclass correlation (ICC), paired samples t-tests, and typical error were used to assess test-retest reliability. To assess construct validity, gender and RTSQ were entered into a regression model predicting MFS. The rank order repeatability of the RTSQ was high (ICC = 0.88). The model explained 39% of the variance in MFS (p ≤ 0.001) and RTSQ (r = 0.40, p ≤ 0.001) was a significant predictor. This study has demonstrated the construct validity and test-retest reliability of the RTSB in a sample of adolescents. The RTSB can reliably rank participants in regards to their resistance training competency and has the necessary sensitivity to detect small changes in resistance training skill proficiency.

The aim of this study was to determine the efficacy and feasibility of a resistance-training (RT) and lifestyle-activity program for sedentary older adults. Eligible participants (N = 44) were randomized to an 8-wk intervention or a control group. The primary outcome was lower body muscle strength, and participants completed a range of secondary outcomes. There was a significant group-by-time interaction for lower body muscle strength (difference = 3.9 repetitions [reps], 95% CI = 2.0-5.8 reps; p < .001; d = 1.0). Changes in secondary outcomes were generally small and not statistically significant. Attendance and program satisfaction were both high. A combined elastic-tubing RT and lifestyle-activity program delivered in the community setting is an efficacious and feasible approach to improve health in sedentary older adults.

Objectives: Resistance training in untrained adolescents can positively effect health-related fitness as well as improve muscular power and sports performance. The impact of resistance training on adolescent athletes is less clear. The purpose of this review is to determine the effectiveness of resistance training programs on muscular power and sports performance in adolescent athletes., Design: Systematic review and meta-analysis of previously published studies investigating resistance training in adolescent athlete populations., Methods: A systematic search of Medline, Embase, and SPORTDiscus databases was conducted on 21st March 2011 to identify studies evaluating resistance training programs on power and sports performance in adolescent athletes., Results: Thirty-four studies were identified. All but two of the studies reported at least one statistically significant improvement in an alactic muscular power outcome. The most common indicators of alactic power were vertical jump (25 studies) and sprint running (13 studies) performance. Fourteen studies provided data to allow for pooling of results in a meta-analysis. A positive effect was detected for resistance training programs on vertical jump performance (mean difference 3.08 [95% CI 1.65, 4.51], Z=4.23 [P<0.0001])., Conclusions: There is sufficient evidence to conclude that resistance-training interventions can improve muscular power in adolescent athletes. A positive effect on sports performance attributable to participation in resistance training was reported by almost half the included studies, however limited objective evidence to support these claims was found. Improvements in motor performance skills, such as jumping, are widely stated as indicators of improvements in sporting performance., (Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

A poor understanding of behaviour change mechanisms has hindered the development of effective physical activity interventions. The aim of this study was to identify potential mediators of change in a home-based resistance training (RT) program for obese individuals with type 2 diabetes. Obese individuals with type 2 diabetes (N = 48) were randomly allocated to either an RT intervention (n = 27) or a control group (n = 21) for the 16-week study period. The study sample included 16 men and 32 women and the mean age of participants was 54.4 (±11.7) years. Participants in the RT group received a multi-gym and dumbbells and home supervision from a certified personal trainer. RT behaviour was measured using a modified Godin Leisure Time Questionnaire. Social-cognitive constructs were measured and tested in a mediating variable framework using a product-of-coefficients test. The intervention had a significant effect on RT behaviour (p < 0.001) and muscular strength (p < 0.001). The intervention had a significant effect on RT planning strategies (p < 0.01), which mediated the effect of the intervention on RT behaviour. The home-based RT program successfully targeted participants' RT planning strategies which contributed to their exercise adherence.

It has been suggested that conditioning programmes have the potential to improve golf performance through fitness adaptations. The primary aim of this systematic review was to evaluate the effectiveness of conditioning programmes on measures of golf-related fitness and golf performance. Four electronic library databases were searched and the quality of the studies was assessed using criteria adapted from the Consolidated Standard of Reporting Trials statement. Thirteen studies satisfied our criteria for inclusion. Nine studies involved middle-aged to older male recreational golfers and four studies used younger more skilled golfers. Conditioning programmes involved the use of machine weights, free weights, medicine balls, and elastic bands, and most studies included a flexibility component. Most studies assessed changes in fitness characteristics and generally resulted in improvements. All but two of the studies assessed changes in club head speed and reported increases. The findings from this review suggest that strength and conditioning programmes can have a positive effect on the golf swing and fitness characteristics of golfers. The majority of studies in this review evaluated the effects of generic conditioning programmes on fitness characteristics and club head speed. Future studies should investigate the effects of more golf-specific strength and conditioning programmes to improve fitness and overall golf performance.

Objective: The aim of this study was to evaluate the efficacy and feasibility of two school-based RT programs to improve muscular fitness and body composition in adolescents., Methods: The study was conducted in Australia from July 2008 to June 2009. Participants [n=108, mean age (SD)=15.0 (0.7) years] were randomized to free weights (n=37) or elastic tubing (n=41) RT groups and a control group was recruited (n=30). Participants in the RT groups completed 2 sets of 10-12 repetitions on 10 exercises for 8 weeks. Waist circumference, body composition (bioelectrical impedance analysis) and muscular strength (bench press and leg press) were assessed at baseline and posttest., Results: Boys (p<0.001) and girls (p<0.01) in both RT groups improved their body composition over the study period. Boys in both RT groups significantly improved both upper and lower body strength and their improvements were significantly greater than changes observed in the control group. Girls in the free weights groups achieved larger improvements in lower body strength compared to the control group (p<0.05)., Conclusions: Free weights and elastic tubing RT are feasible and effective strategies for improving aspects of health-related fitness in adolescents., (Copyright 2009 Published by Elsevier Inc. Published by Elsevier Inc. All rights reserved.)