Resistance training leads to large improvements in strength and moderate improvements in physical function in adults who are overweight or obese: a systematic review

QuestionsWhat are the effects of resistance training on muscle strength, physical function and muscle power in adults who are overweight or obese? Which factors moderate the effects?DesignSystematic review of randomised controlled trials, with random effects meta-analyses and meta-regressions.ParticipantsAdults who are overweight or obese.InterventionResistance training lasting ≥ 4 weeks.Outcome measuresMuscle strength, muscle power and physical function.ResultsThirty trials with 1,416 participants met the eligibility criteria. Pooled analyses indicated that resistance training has a large beneficial effect on muscle strength (SMD 1.39, 95% CI 1.05 to 1.73, I2 = 85%) and a moderate effect on physical function (SMD 0.67, 95% CI 0.25 to 1.08, I2 = 71%) in adults who are overweight or obese. However, the effect of resistance training on muscle power was unclear (SMD 0.42, 95% CI −3.3 to 4.2, I2 = 46%). The effect of resistance training on strength was greatest for the upper body (versus lower/whole body: β = 0.35, 95% CI 0.05 to 0.66) and in dynamic strength tests (versus isometric/isokinetic: β = 1.20, 95% CI 0.60 to 1.81), although trials judged to have good methodological quality reported statistically smaller effects (versus poor/fair quality: β = −1.21, 95% CI −2.35 to −0.07). Concomitant calorie restriction did not modify strength gains but reduced the effect of resistance training on physical function (β = −0.79, 95% CI −1.41 to −0.17). Small study effects were evident for strength outcomes (β = 5.9, p < 0.001).ConclusionsResistance training has a large positive effect on muscle strength and a moderate effect on physical function in adults who are overweight or obese. However, the effect of resistance training on muscle power is uncertain. In addition, concomitant calorie restriction may compromise the functional adaptations to resistance training

Effectiveness of diet and physical activity interventions amongst adults attending colorectal and breast cancer screening: a systematic review and meta-analysis

Purpose: To estimate the effectiveness of tailored physical activity and dietary interventions amongst adults attending colorectal and breast cancer screening. Methods: Five literature databases were systematically searched to identify randomised controlled trials (RCTs) of tailored physical activity and/or dietary interventions with follow-up support initiated through colorectal and breast cancer screening programmes. Outcomes included markers of body fatness, physical activity, and dietary intake. Mean differences (MDs) or standardised mean differences (SMDs) with 95% confidence intervals (CIs) were pooled using random effects models. Results: Five RCTs met the inclusion criteria encompassing a total of 722 participants. Diet and physical activity interventions led to statistically significant reductions in body mass (MD − 1.6 kg, 95% CI − 2.7 to − 0.39 kg; I2 = 81%; low quality evidence), body mass index (MD − 0.78 kg/m2, 95% CI − 1.1 to − 0.50 kg/m2; I2 = 21%; moderate quality evidence), and waist circumference (MD − 2.9 cm, 95% CI − 3.8 to − 1.91; I2 = 0%; moderate quality evidence), accompanied by an increase in physical activity (SMD 0.31, 95% CI 0.13 to 0.50; I2 = 0%; low quality evidence) and fruit and vegetable intake (SMD 0.33, 95% CI 0.01 to 0.64; I2 = 51%; low quality evidence). Conclusion: There is low quality evidence that lifestyle interventions involving follow-up support lead to modest weight loss and increased physical activity and fruit and vegetable intake. Due to the modest intervention effects, low quality of evidence and small number of studies, further rigorously designed RCTs with long-term follow-up of modifiable risk factors and embedded cost–benefit analyses are warranted (PROSPERO ref: CRD42020179960)

The Effect of Complex Training on Muscle Architecture in Rugby League Players

PURPOSE: To compare the effects of variable-resistance complex training (VRCT) versus traditional complex training (TCT) on muscle architecture in rugby league players during a 6-week mesocycle. METHODS: Twenty-four rugby league players competing in the British University & Colleges Sport (BUCS) Premier North Division were randomized to VRCT (n = 8), TCT (n = 8), or control (n = 8). Experimental groups completed a 6-week lower-body complex training intervention (2×/wk), which involved alternating high-load resistance exercise with plyometric exercise in the same session. The VRCT group performed resistance exercises at 70% of 1-repetition maximum (1RM) + 0% to 23% of 1RM from band resistance with a 90-second intracontrast rest interval, whereas the TCT group performed resistance exercise at 93% of 1RM with a 4-minute intracontrast rest interval. Muscle thickness (MT), pennation angle, and fascicle length (Lf) were assessed for the vastus lateralis (VL) and gastrocnemius medialis using ultrasound imaging. RESULTS: Both TCT and VRCT groups significantly improved VL MT and VL Lf compared with control (all P < .05). Standardized within-group changes in MT and Lf (Cohen dav ± 95% CI) were moderate for TCT (dav = 0.91 ± 1.0; dav = 1.1 ± 1.1) and unclear for VRCT (dav = 0.44 ± 0.99; dav = 0.47 ± 0.99), respectively. Differences in change scores between TCT and VRCT were unclear. CONCLUSIONS: VRCT and TCT can be utilized during the competitive season to induce favorable MT and Lf muscle architecture adaptations for the VL. TCT may induce greater muscle architecture adaptations of the VL, whereas VRCT may be of more practical value given the shorter intracontrast rest interval between resistance and plyometric exercises

The Effect of Complex Training on Physical Performance in Rugby League Players

Purpose: To compare the effects of variable-resistance complex training (VRCT) versus traditional complex training (TCT) on strength, power, speed, and leg stiffness (Kleg) in rugby league players during a 6-week mesocycle. Methods: Twenty-four rugby league players competing in the British University and Colleges Sport Premier North Division were randomized to VRCT (n = 8), TCT (n = 8), or control (CON; n = 8). Experimental groups completed a 6-week lower-body complex training intervention (2×/wk) that involved alternating high-load resistance exercise with plyometric exercise within the same session. The VRCT group performed resistance exercises at 70% of 1-repetition maximum (1RM) + 0% to 23% of 1RM from band resistance with a 90-second intracontrast rest interval, whereas the TCT group performed resistance exercise at 93% of 1RM with a 4-minute intracontrast rest interval. Back-squat 1RM, countermovement jump peak power, reactive strength index, sprint times, and Kleg were assessed pretraining and post-training. Results: VRCT and TCT significantly improved 1RM back squat, countermovement jump peak power, and 5-m sprint time (all P < .05). VRCT also improved Kleg, whereas TCT improved 10- and 20-m sprint times (all P < .05). Between groups, both VRCT and TCT improved 1RM back squat compared with CON (both P < .001). Additionally, VRCT improved Kleg compared with CON (right leg: P = .016) and TCT improved 20-m sprint time compared with CON (P = .042). Conclusions: VRCT and TCT can be implemented during the competitive season to improve strength, power, and 5-m sprint time. VRCT may lead to greater improvements in reactive strength index and Kleg, whereas TCT may enhance 10- and 20-m sprint times

Effect of home‐based resistance training performed with or without a high‐speed component in adults with severe obesity

1) To evaluate the effects of walking and home‐based resistance training on function, strength, power, anthropometry and quality of life (QoL) in adults with severe obesity, and 2) to assess whether performing resistance exercises with maximal concentric velocity provides additional benefits compared with traditional slow‐speed resistance training.MethodsAdults with a body mass index of ≥40 kg/m2 were randomised to slow‐speed strength training (ST; n = 19) or high‐speed power training (PT; n = 19). Both groups completed a walking intervention and home‐based resistance training (2x/week for 6‐months). The PT group performed resistance exercises with maximal intended concentric velocity, whereas the ST group maintained a slow (2‐s) concentric velocity.ResultsAt 6‐months, weight loss was ~3 kg in both groups. Both groups significantly improved function (gz = 1.04‐1.93), strength (gz = 0.65‐1.77), power (gz = 0.66‐0.85), contraction velocity (gz = 0.65‐1.12) and QoL (gz = 0.62‐1.54). Between‐group differences in shoulder press velocity (‐0.09 m·s‐1, gs = ‐0.95 [‐1.63, ‐0.28]) and six‐minute walk test (‐16.9 m, gs = ‐0.51 [‐1.16, 0.13]) favoured the PT group.ConclusionsHome‐based resistance training and walking leads to significant improvements in functional and psychological measures in adults with severe obesity. In addition, considering the between‐group effect sizes and their uncertainty, performing resistance exercises with maximal concentric speed is a simple adjustment to conventional resistance training that yields negligible negative effects but potentially large benefits on walking capacity and upper‐limb contraction velocity

Short-Term Training and Detraining Effects of Supervised vs. Unsupervised Resistance Exercise in Aging Adults

Orange, ST, Marshall, P, Madden, LA, and Vince, RV. Short-term training and detraining effects of supervised vs. unsupervised resistance exercise in aging adults. J Strength Cond Res 33(10): 2733-2742, 2019-This study compared the effects of a 4-week supervised (SUP) resistance training program and unsupervised (UNSUP) resistance training program followed by 12 weeks of detraining (DET). Thirty-six healthy aging adults (age: 53.6 ± 3.6 years; body mass index: 28.3 ± 5.1 kg·m) were randomly allocated to an SUP group (n = 17) or a UNSUP group (n = 19). Participants completed 3 training sessions per week using resistance bands and body weight movements. Measures of physical performance were administered at baseline, at the end of the training program, and after the DET period. Function was assessed with the 6-minute walk test (6MWT), timed up-and-go (TUG), 30-second chair sit-to-stand (STS), stair-climb test (SCT), 40-m fast-paced walk test (FPWT) and sit-and-reach test (SRT), whereas the isometric midthigh pull (IMTP) and hand grip test were used to measure muscle strength. After training, improvements in performance were found in the 6MWT, TUG, 30-second chair STS, SCT, FPWT, SRT, and IMTP (p ≤ 0.05), with no significant differences between groups (p > 0.05). In addition, most of the training-induced improvements remained significantly above baseline values after the DET period (p ≤ 0.05). No significant between-group differences were observed after training or DET (p > 0.05). Four weeks of either SUP or UNSUP resistance training is sufficient to substantially improve muscle strength and function in aging adults, and these gains are largely preserved after prescribed exercise cessation. Home-based resistance training seems to be a practical and effective alternative to traditional SUP programs that may help circumvent many barriers to physical activity in aging adults

Recall, perceptions and determinants of receiving physical activity advice amongst cancer survivors: a mixed-methods survey

Purpose: This study explored cancer survivors’ views and experiences of receiving physical activity advice post-diagnosis. We also determined the influence of sociodemographic characteristics on the recall of physical activity advice and whether receiving advice was associated with meeting physical activity guidelines. Methods: An anonymised, mixed-methods, 27-item survey was distributed to cancer survivors via online cancer communities in the UK. Results: Of the 242 respondents, 52% recalled receiving physical activity advice. Of those who recalled receiving advice, only 30% received guidance on type of physical activity and 14% were referred to another source of information or exercise specialist. Advice was most often given after treatment cessation, with only 19% of respondents receiving advice during active treatment. Most respondents (56%) expressed a need for further information. There was no evidence of associations between sociodemographic characteristics and recall of physical activity advice. However, cancer survivors who perceived the physical activity advice they received as being appropriate (odds ratio [OR] 3.8, 95% confidence interval [95% CI]: 1.4–10.7) and those with a higher level of education (OR 3.2, 95% CI: 1.8–5.8) were more likely to meet aerobic exercise guidelines. Females were less likely to meet resistance exercise guidelines than males (OR 0.44, 95% CI: 0.21–0.90). Conclusion: There is scope to improve the provision of physical activity advice in cancer care by providing advice in a timely manner after diagnosis, referring patients to a suitable exercise or rehabilitation specialist when indicated, and using a tailored approach to ensure the advice is appropriate for specific sociodemographic groups

The serological responses to acute exercise in humans reduce cancer cell growth in vitro: A systematic review and meta‐analysis

We systematically reviewed and meta‐analyzed the effects of acute exercise‐conditioned serum on cancer cell growth in vitro. Five literature databases were systematically searched for studies that measured cancer cell growth after exposure to human sera obtained before and immediately after an acute bout of exercise. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were pooled using a three‐level random‐effects model. Meta‐regressions were also performed with participant age and disease status, exercise type, cell line TP53 status, and serum incubation time entered as covariates. Seven studies met the inclusion criteria encompassing a total of 21 effect estimates and 98 participants. Exercise‐conditioned serum significantly reduced cancer cell growth compared with preexercise serum (SMD = −1.23, 95% CI: −1.96 to −0.50; p = .002; I2 = 75.1%). The weighted mean reduction as a percentage of preexercise values was 8.6%. The overall treatment effect and magnitude of heterogeneity were not statistically influenced by any covariate. There were concerns regarding the risk of bias within individual studies and Egger's test of the intercept showed evidence of small study effects (β = −3.6, p = .004). These findings provide in vitro evidence that the transient serological responses to acute exercises reduce cancer cell growth, although many questions remain regarding the underlying mechanistic pathways and potential effect modifiers. To strengthen this evidence‐base, future studies should seek to reduce the risk of bias by using more rigorous experimental designs, and consider using 3D cell culture models to better replicate in vivo tumor conditions. PROSPERO registration: CRD42020161333

Effect of exercise before and/or during taxane-containing chemotherapy treatment on chemotherapy-induced peripheral neuropathy symptoms in women with breast cancer: systematic review and meta-analysis

Purpose To systematically review and meta-analyse the efficacy of exercise interventions delivered before and/or during taxane-containing chemotherapy regimens on chemotherapy-induced peripheral neuropathy (CIPN), fatigue, and health-related quality of life (HR-QoL), in women with breast cancer.Methods Seven electronic databases were systematically searched for randomised controlled trials (RCTs) reporting on the effects of exercise interventions in women with breast cancer receiving taxane-containing chemotherapeutic treatment. Meta-analyses evaluated the effects of exercise on CIPN symptoms, fatigue, and HR-QoL.Results Ten trials involving exercise interventions ranging between 2 and 12 months were included. The combined results of four RCTs consisting of 171 participants showed a reduction in CIPN symptoms following exercise compared with usual care (standardised mean difference − 0.71, 95% CI − 1.24 to − 0.17, p = 0.012; moderate-quality evidence, I2 = 76.9%). Pooled results from six RCTs with 609 participants showed that exercise interventions before and/or during taxane-containing chemotherapy regimens improved HR-QoL (SMD 0.42, 95% CI 0.07 to 0.76, p = 0.03; moderate-quality evidence, I2 = 49.6%). There was no evidence of an effect of exercise on fatigue (− 0.39, 95% CI − 0.95 to 0.18, p = 0.15; very low-quality evidence, I2 = 90.1%).Conclusions This systematic review found reduced levels of CIPN symptoms and an improvement in HR-QoL in women with breast cancer who exercised before and/or during taxane-based chemotherapy versus usual care controls.Implications for Cancer Survivors This evidence supports the role of exercise as an adjunctive treatment for attenuating the adverse effects of taxane-containing chemotherapy on CIPN symptoms and HR-QoL

Test-Retest reliability of a commercial linear position transducer (GymAware PowerTool) to measure velocity and power in the Back Squat and Bench Press

This study examined the test-retest reliability of the GymAware PowerTool (GYM) to measure velocity and power in the free-weight back squat and bench press. Twenty-nine academy rugby league players (age: 17.6 ± 1.0 years; body mass: 87.3 ± 20.8 kg) completed 2 test-retest sessions for the back squat followed by 2 test-retest sessions for the bench press. GYM measured mean velocity (MV), peak velocity (PV), mean power (MP), and peak power at 20, 40, 60, 80, and 90% of 1 repetition maximum (1RM). GYM showed good reliability (intraclass correlation coefficient [ICC] and standard error of measurement percentage, respectively) for the measurement of MV at loads of 40 (0.77, 3.9%), 60 (0.83, 4.8%), 80 (0.83, 5.8%), and 90% (0.79, 7.9%) of 1RM in the back squat. In the bench press, good reliability was evident for PV at 40 (0.82, 3.9%), 60 (0.81, 5.1%), and 80% (0.77, 8.4%) of 1RM, and for MV at 80 (0.78, 7.9%) and 90% (0.87, 9.9%) of 1RM. The measurement of MP showed good to excellent levels of reliability across all relative loads (ICC ≥0.75). In conclusion, GYM provides practitioners with reliable kinematic information in the back squat and bench press, at least with loads of 40–90% of 1RM. This suggests that strength and conditioning coaches can use the velocity data to regulate training load according to daily readiness and target specific components of the force-velocity curve. However, caution should be taken when measuring movement velocity at load