Efficacy of resistance training during adjuvant chemotherapy and radiation therapy in cancer care: a systematic review and meta-analysis.

PURPOSE: To determine the effect of resistance training during adjuvant chemotherapy and radiation therapy in cancer patients on measures of lean mass and muscle strength. Secondary aims were to analyse the prescription and tolerability of supervised resistance training in this population. METHODS: EMBASE, Medline, CINAHL, Cochrane Library and Web of Science were searched from inception until 29 March 2021. Eligible randomised controlled trials (RCTs) examining supervised resistance training > 6 weeks duration during adjuvant chemotherapy and/or radiation therapy in cancer patients with objective measurement of muscle strength and/or lean mass were included. The meta-analysis was performed using Revman 5.4. RESULTS: A total of 1910 participants from 20 articles were included (mean age: 54 years, SD = 10) and the majority were female (76.5%). Resistance training was associated with a significant increase in upper body strength (standardised mean difference (SMD) = 0.57, 95% CI 0.36 to 0.79, I2 = 64%, P < 0.0001), lower body strength (SMD = 0.58, 95% CI 0.18 to 0.98, I2 = 91%, P = 0.005), grip strength (mean difference (MD) = 1.32, 95% CI 0.37 to 2.27, I2 = 0%, P < 0.01) and lean mass (SMD = 0.23, 95% CI 0.03 to 0.42, I2 = 0%, P = 0.02). A P value of < 0.05 was considered statistically significant. The quality of the studies included was moderate to high with low risk of bias as per the PEDro scale. CONCLUSION: Resistance training is an effective adjunct therapy to improve muscle strength and lean mass in cancer patients undergoing chemotherapy and/or radiation therapy. PROSPERO REGISTRATION NUMBER: CRD42020180643.

Elite female athletes' experiences of symptoms of pelvic floor dysfunction: A systematic review.

INTRODUCTION AND AIMS: Pelvic floor dysfunction (PFD) is a collection of signs, symptoms and conditions affecting the pelvic floor and urinary incontinence (UI) is the most common type of PFD. Recent systematic reviews have indicated a higher prevalence of UI among female athletes compared to their non-athletic counterparts. To date, no review has been undertaken to investigate female athletes' experiences of PFD. This review aims to offer insight and understanding, through aggregation, summary, synthesis and interpretation of findings from studies that report elite female athletes' experiences of symptoms of PFD. METHODS: The review protocol was registered in PROSPERO in August 2020. A systematic search was conducted in Embase, MEDLINE (OVID), Cochrane Library, CINAHL, PsycINFO and Web of Science for studies published in the English language reporting elite female athletes' experiences of symptoms of PFD. This review included primary research studies that involved elite female athletes of any age or ethnicity. RESULTS: Of the 1922 citations retrieved in the search, 32 studies met the methodological criteria for data extraction and analysis. Five main themes emerged: (1) triggers for symptoms of PFD; (2) strategies adopted by athletes to manage/mitigate symptoms of PFD; (3) impact on QOL/daily life; (4) impact on performance; (5) impact on emotions. CONCLUSIONS: The findings of this review suggest a need to further explore the experiences of PFD among elite female athletes and it is suggested that future research should adopt qualitative methods or incorporate a qualitative component.

The effect of diurnal variation in exercise-induced bronchoconstriction.

Objective: Exercise-induced bronchoconstriction (EIB) is an acute, transient narrowing of the airway as a result of exercise. Diurnal variation in asthma is well-established, however, few studies have investigated diurnal variability in EIB; no study has used eucapnic voluntary hyperpnea (EVH). The aim of this study was to examine circadian variability in EIB using EVH.Methods: Fourteen recreationally-active males with mild to moderate asthma and nine healthy controls were randomized to first complete either an AM (07:00-08:00) or PM (17:00-18:00) EVH challenge, followed by the alternate test 34 h to 7 days later. The EVH protocol comprised of six-minutes of hyperventilation of a 5% CO2 gas at a minimum ventilation rate of 21 × FEV1 min-1. The primary outcome measure was FEV1 pre- and post-EVH.Results: We observed no diurnal effect on EIB in the asthma group. The minimum observed post-EVH FEV1 in the asthma cohort was 3.58 ± 0.95 L in AM and 3.62 ± 0.87 L in PM tests, corresponding to a 15.0 ± 15.3% vs. 14.9 ± 14.7% reduction from baseline, respectively. The asthma group showed similar baseline FEV1 before AM (4.21 ± 0.79 L) and PM (4.25 ± 0.65 L) tests. No difference was observed in minute ventilation between AM (26.1 ± 3.4 × FEV1 min-1) and PM (25.6 ± 3.8 × FEV1 min-1) tests for the asthma cohort. Controls displayed no significant changes in FEV1 or minute ventilation between tests.Conclusions: When baseline pulmonary function is similar, this study suggests that time-of-day has no effect on EIB in mild to moderate asthma.

Improving diabetes care and outcomes with community health workers.

BACKGROUND: Type II diabetes continues to be a major health problem in USA, particularly in minority populations. The Diabetes Equity Project (DEP), a clinic-based diabetes self-management and education program led by community health workers (CHWs), was designed to reduce observed disparities in diabetes care and outcomes in medically underserved, predominantly Hispanic communities. OBJECTIVE: The purpose of this study was to evaluate the impact of the DEP on patients' clinical outcomes, diabetes knowledge, self-management skills, and quality of life. METHODS: The DEP was implemented in five community clinics from 2009 to 2013 and 885 patients completed at least two visits with the CHW. Student's paired t-tests were used to compare baseline clinical indicators with indicators obtained from patients' last recorded visit with the CHW and to assess differences in diabetes knowledge, perceived competence in managing diabetes, and quality of life. A mixed-effects model for repeated measures was used to examine the effect of DEP visits on blood glucose (HbA1c), controlling for patient demographics, clinic and enrolment date. RESULTS: DEP patients experienced significant (P < 0.0001) improvements in HbA1c control, blood pressure, diabetes knowledge, perceived competence in managing diabetes, and quality of life. Mean HbA1c for all DEP patients decreased from 8.3% to 7.4%. CONCLUSION: Given the increasing prevalence of diabetes in USA and documented disparities in diabetes care and outcomes for minorities, particularly Hispanic patients, new models of care such as the DEP are needed to expand access to and improve the delivery of diabetes care and help patients achieve improved outcomes.

A comparison of electromyography and stroke kinematics during ergometer and on-water rowing.

This study assessed muscle recruitment patterns and stroke kinematics during ergometer and on-water rowing to validate the accuracy of rowing ergometry. Male rowers (n = 10; age 21 ± 2 years, height 1.90 ± 0.05 m and body mass 83.3 ± 4.8 kg) performed 3 × 3 min exercise bouts, at heart and stroke rates equivalent to 75, 85 and 95% VO2peak, on both dynamic and stationary rowing ergometers, and on water. During exercise, synchronised data for surface electromyography (EMG) and 2D kinematics were recorded. Overall muscle activity was quantified by the integration of rmsEMG and averaged for each 10% interval of the stroke cycle. Muscle activity significantly increased in rectus femoris (RF) and vastus medialis (VM) (P <0.01), as exercise intensity increased. Comparing EMG data across conditions revealed significantly (P <0.05) greater RF and VM activity during on-water rowing at discrete 10% intervals of stroke cycle. In addition, the drive/recovery ratio was significantly lower during dynamic ergometry compared to on-water (40 ± 1 vs. 44 ± 1% at 95%, P <0.01). Results suggest that significant differences exist while comparing recruitment and kinematic patterns between on-water and ergometer rowing. These differences may be due to altered acceleration and deceleration of moving masses on-ergometer not perfectly simulating the on-water scenario.

Cross-site evaluation of the Alliance to Reduce Disparities in Diabetes: clinical and patient-reported outcomes.

Alliance programs implemented multilevel, multicomponent programs inspired by the chronic care model and aimed at reducing health and health care disparities for program participants. A unique characteristic of the Alliance programs is that they did not use a fixed implementation strategy common to programs using the chronic care model but instead focused on strategies that met local community needs. Using data provided by the five programs involved in the Alliance, this evaluation shows that of the 1,827 participants for which baseline and follow-up data were available, the program participants experienced significant decreases in hemoglobin A1c and blood pressure compared with a comparison group. A significant time by study group interaction was observed for hemoglobin A1c as well. Over time, more program participants met quality indicators for hemoglobin A1c and blood pressure. Those participants who attended self-management classes and experienced more resources and support for self-management attained more benefit. In addition, program participants experienced more diabetes competence, increased quality of life, and improvements in diabetes self-care behaviors. The cost-effectiveness of programs ranged from $23,161 to $61,011 per quality-adjusted life year. In sum, the Alliance programs reduced disparities and health care disparities for program participants.

Acute differences in foot strike and spatiotemporal variables for shod, barefoot or minimalist male runners.

This study compared stride length, stride frequency, contact time, flight time and foot-strike patterns (FSP) when running barefoot, and in minimalist and conventional running shoes. Habitually shod male athletes (n = 14; age 25 ± 6 yr; competitive running experience 8 ± 3 yr) completed a randomised order of 6 by 4-min treadmill runs at velocities (V1 and V2) equivalent to 70 and 85% of best 5-km race time, in the three conditions. Synchronous recording of 3-D joint kinematics and ground reaction force data examined spatiotemporal variables and FSP. Most participants adopted a mid-foot strike pattern, regardless of condition. Heel-toe latency was less at V2 than V1 (-6 ± 20 vs. -1 ± 13 ms, p < 0.05), which indicated a velocity related shift towards a more FFS pattern. Stride duration and flight time, when shod and in minimalist footwear, were greater than barefoot (713 ± 48 and 701 ± 49 vs. 679 ± 56 ms, p < 0.001; and 502 ± 45 and 503 ± 41 vs. 488 ±4 9 ms, p < 0.05, respectively). Contact time was significantly longer when running shod than barefoot or in minimalist footwear (211±30 vs. 191 ± 29 ms and 198 ± 33 ms, p < 0.001). When running barefoot, stride frequency was significantly higher (p < 0.001) than in conventional and minimalist footwear (89 ± 7 vs. 85 ± 6 and 86 ± 6 strides·min(-1)). In conclusion, differences in spatiotemporal variables occurred within a single running session, irrespective of barefoot running experience, and, without a detectable change in FSP. Key pointsDifferences in spatiotemporal variables occurred within a single running session, without a change in foot strike pattern.Stride duration and flight time were greater when shod and in minimalist footwear than when barefoot.Stride frequency when barefoot was higher than when shod or in minimalist footwear.Contact time when shod was longer than when barefoot or in minimalist footwear.Spatiotemporal variables when running in minimalist footwear more closely resemble shod than barefoot running.

Cost-utility analysis of community-based interventions for hypertension control in Vietnam.

Between 2010 and 2011, stakeholders implemented a multi-faceted community-based intervention in response to the escalating issue of uncontrolled hypertension in Hung Yen province, Vietnam. This initiative integrated expanded community health worker services, home blood pressure self-monitoring, and a unique "storytelling intervention" into routine clinical care. From the limited societal perspective, our study evaluates the cost-effectiveness of this intervention using a Markov model with a one-year cycle over a lifetime horizon. The analysis, based on a cohort of 671 patients, reveals a lifetime incremental cost of approximately VND 90.37 million (USD 3,930) per quality-adjusted life year (QALY) gained. With a willingness to pay at three times GDP (VND 259.2 million per QALY), the intervention proves cost-effective 80% of the time. This research underscores the potential of the community-based approach to effectively control hypertension, offering valuable insights into its broader implications for public health.

Challenges in using electronic health record data for CER: experience of 4 learning organizations and solutions applied.

OBJECTIVE: To document the strengths and challenges of using electronic health records (EHRs) for comparative effectiveness research (CER). METHODS: A replicated case study of comparative effectiveness in hypertension treatment was conducted across 4 health systems, with instructions to extract data and document problems encountered using a specified list of required data elements. Researchers at each health system documented successes and challenges, and suggested solutions for addressing challenges. RESULTS: Data challenges fell into 5 categories: missing data, erroneous data, uninterpretable data, inconsistencies among providers and over time, and data stored in noncoded text notes. Suggested strategies to address these issues include data validation steps, use of surrogate markers, natural language processing, and statistical techniques. DISCUSSION: A number of EHR issues can hamper the extraction of valid data for cross-health system comparative effectiveness studies. Our case example cautions against a blind reliance on EHR data as a single definitive data source. Nevertheless, EHR data are superior to administrative or claims data alone, and are cheaper and timelier than clinical trials or manual chart reviews. All 4 participating health systems are pursuing pathways to more effectively use EHR data for CER.A partnership between clinicians, researchers, and information technology specialists is encouraged as a way to capitalize on the wealth of information contained in the EHR. Future developments in both technology and care delivery hold promise for improvement in the ability to use EHR data for CER.

Comparative effectiveness research using electronic health records: impacts of oral antidiabetic drugs on the development of chronic kidney disease.

PURPOSE: Little is known about the comparative effects of common oral antidiabetic drugs ([OADs] metformin, sulfonylureas, or thiazolidinediones [THZs]) on chronic kidney disease (CKD) outcomes in patients newly diagnosed with type 2 diabetes (T2DM) and followed in community primary care practices. Electronic health records (EHRs) were used to evaluate the relationships between OAD class use and incident proteinuria and prevention of glomerular filtration rate decline. METHODS: A retrospective cohort study on newly diagnosed T2D cases requiring OADs documented in the EHRs of two primary care networks between 1998 and 2009 was conducted. CKD outcomes were new-onset proteinuria and estimated GFR (eGFR) falling below 60 ml/min/1.73 m(2). OAD exposures defined cohorts. Hazard ratios represent differential CKD outcome risk per year of OAD class use. RESULTS: A total of 798 and 977 patients qualified for proteinuria and eGFR outcome analyses, respectively. With metformin as the reference group, sulfonylurea exposure trended toward association with an increased risk of developing proteinuria ([adjusted hazard ratio; 95% CI] 1.27; 0.93, 1.74); proteinuria risk associated with THZ exposure (1.00; 0.70, 1.42) was similar to metformin. Compared with metformin, sulfonylurea exposure was associated with an increased risk of eGFR reduction to <60 ml/min/1.73 m(2) (1.41; 1.05, 1.91). THZ exposure (1.04; 0.71, 1.50) was not associated with change in the risk of eGFR decline. CONCLUSIONS: In a primary care population, metformin appeared to decrease the risk of CKD development compared with sulfonlyureas; risks of CKD development between metformin and THZs were similar. EHR use in pharmacotherapy comparative effectiveness research creates specific challenges and study limitations.

The incident user design in comparative effectiveness research.

Comparative effectiveness research includes cohort studies and registries of interventions. When investigators design such studies, how important is it to follow patients from the day they initiated treatment with the study interventions? Our article considers this question and related issues to start a dialogue on the value of the incident user design in comparative effectiveness research. By incident user design, we mean a study that sets the cohort's inception date according to patients' new use of an intervention. In contrast, most epidemiologic studies enroll patients who were currently or recently using an intervention when follow-up began. We take the incident user design as a reasonable default strategy because it reduces biases that can impact non-randomized studies, especially when investigators use healthcare databases. We review case studies where investigators have explored the consequences of designing a cohort study by restricting to incident users, but most of the discussion has been informed by expert opinion, not by systematic evidence.

Prediction of Rowing Functional Threshold Power Using Body Mass, Blood Lactate and GxT Peak Power Data.

Functional Threshold Power (FTP) is a validated index of a maximal quasi steady-state cycling intensity. The central component of the FTP test is a maximal 20-min time-trial effort. A model to predict FTP from a cycling graded exercise test (m-FTP) was published that estimated FTP without the requirement of the exhaustive 20-min time-trial. The predictive model (m-FTP) was trained (developed to find the best combination of weights and bias) on a homogenous group of highly-trained cyclists and triathletes. This investigation appraised the external validity of the m-FTP model vis-à-vis the alternate modality of rowing. The reported m-FTP equation purports to be sensitive to both changing levels of fitness, and exercise capacity. To assess this claim, eighteen (7 female, 11 male) heterogeneously-conditioned rowers were recruited from regional rowing clubs. The first rowing test was a 3-min graded incremental test with a 1-min break between increments. The second test was a rowing adapted FTP test. There were no significant differences between rowing FTP (r-FTP) and m-FTP (230 ± 64 versus 233 ± 60 W, respectively, F = 1.13, P = 0.80). Computed Bland-Altman 95% LoA between r-FTP and m-FTP were (-18 W to + 15 W), sy.x was 7 W, and 95 %CI of regression were 0.97 to 0.99. The r-FTP equation was demonstrated to be effective in predicting a rowers 20-min maximum power; further appraisal of the physiological response to rowing for 60-min at the corresponding calculated FTP requires investigation.

Does exercise therapy improve pulmonary function in patients with Adolescent Idiopathic Scoliosis?

INTRODUCTION: Exercise therapy is frequently used for treating patients with Adolescent Idiopathic Scoliosis (AIS) however no previous review has evaluated the effect of exercise therapy on pulmonary function in this population. OBJECTIVE: To systematically analyze the literature on the effect of exercise therapy on pulmonary function in patients with AIS. METHODS: A systematic electronic database search (CINAHL, Embase, Medline, Web of Science) was conducted. Manual searches of key reviews and studies were also conducted. Studies that included exercise-based interventions to improve pulmonary function in patients with AIS and reported pre- and post-intervention pulmonary function test scores were included. Test scores were compared using standardized mean difference (SMD) between intervention and control groups in randomized control trials (RCT) and mean ± SD between pre- and post-intervention in prospective intervention studies (PI). Methodological quality was assessed using a modified Downs and Black checklist. RESULTS: Fifteen studies met the inclusion criteria (six RCTs and nine PIs). Results indicated the positive effect of exercise-based therapy on lung volumes (FVC/VC) and FEV1 in patients with AIS. CONCLUSION: Exercise therapy has a positive effect on lung volumes in patients with AIS. The quality of many studies was only 'fair,' therefore more suitably powered higher level clinical trials are required.

The effect of surface compliance on overground running biomechanics. A systematic review and meta-analysis.

The surface upon which running is performed has been suggested as a potential cause of many running-related injuries. It remains unclear, however, what effect surface compliance has on running biomechanics. This study aimed to investigate the effect of surface compliance on overground running biomechanics through a systematic review and meta-analysis. Using the PRISMA Protocols Statement, a search was conducted in three electronic databases (CINAHL, EMBASE, EBSCO) using the following anchoring terms: running, overground surface, biomechanics, kinematics, tibial acceleration, pressure and force. Following de-duplication, title/abstract screening and full-text review, 25 articles (n = 492) were identified which met all inclusion criteria, 22 (n = 392) of which were subsequently included in quantitative synthesis. Random effects analysis found that peak tibial acceleration was significantly lower when running on softer surfaces (P = 0.01, Z = 2.51; SMD = -0.8; 95% CI =-1.42 to -0.18). However, peak vertical ground reaction force, loading rate and ground contact time were not significantly different when comparing hard and soft surfaces. Since peak tibial acceleration has been associated with an increased risk of tibial stress injuries, the results of this meta-analysis suggest that running on softer surfaces to reduce impact stress on the tibia is probably justified to lower the risk of running-related stress injuries.

Contralateral Selectivity of Upper-Limb Motor Pools via Targeted Stimulation of the Cervical Spinal Cord.

Transcutaneous spinal cord stimulation (tSCS) at the cervical level may facilitate improved upper-limb function in those with incomplete tetraplegia. While clinical trials are ongoing, there is still much debate regarding the transmission pathway as well as appropriate stimulation parameters. This study aimed to explore the extent to which cervical tSCS can induce mono-synaptic reflexes in discrete upper-limb motor pools and examine the effects of altering stimulus location and intensity. METHODS: Fourteen participants with intact nervous systems completed two laboratory visits, during which posterior root-muscle reflexes (PRMRs) were evoked via a 3 × 3 cathode matrix applied over the cervical spine. An incremental recruitment curve at the C7 vertebral level was initially performed to attain resting motor threshold (RMT) in each muscle. Paired pulses (1 ms square monophasic with inter-pulse interval of 50 ms) were subsequently delivered at a frequency of 0.25 Hz at two intensities (RMT and RMT + 20%) across all nine cathode positions. Evoked responses to the 1st (PRMR1) and 2nd (PRMR2) stimuli were recorded in four upper-limb muscles. RESULTS: A significant effect of the spinal level was observed in all muscles for PRMR1, with greater responses being recorded caudally. Contralateral stimulation significantly increased PRMR1 in Biceps Brachii (p < 0.05, F = 4.9, η2 = 0.29), Flexor Carpi Radialis (p < 0.05, F = 4.9, η2 = 0.28) and Abductor Pollicis Brevis (p < 0.01, F = 8.9, η2 = 0.89). Post-activation depression (PAD) was also significantly increased with contralateral stimulation in Biceps Brachii (p = 0.001, F = 9.3, η2 = 0.44), Triceps Brachii (p < 0.05, F = 5.4, η2 = 0.31) and Flexor Carpi Radialis (p < 0.001, F = 17.4, η2 = 0.59). CONCLUSIONS: A level of unilateral motor pool selectivity may be attained by altering stimulus intensity and location during cervical tSCS. Optimising these parameters may improve the efficacy of this neuromodulation method in clinical cohorts.

Multimodal analysis of the biomechanical impact of knee angle on the Sit-to-Stand transition.

BACKGROUND: The Sit-to-Stand (STS) transition is one of the most used activities of daily living and vital for independence. Neurological, or physical injuries impairing functional mobility or sensory feedback often require rehabilitative programs or therapeutic interventions. Understanding the biomechanical elements of daily movements and the interaction between these elements may help inform rehabilitation protocols and optimize targeted interventions, such as stimulation protocols. RESEARCH QUESTION: What are the effects of different initial knee angle, arm facilitation and proprioceptive input on leg muscle activation patterns and balance during and after a sit-to-stand? METHODS: EMG of four lower limb muscles were recorded in 20 healthy participants as well centre-of-pressure sway amplitude and velocity, as participants stood from a seated position. Initial knee angles were set to various levels of extension (80°, 90°, 100°) and surface stability and arm facilitation were altered using a foam mat or crossing arms. Data were analysed across 3 phases of the STS transition. RESULTS: More extended knee angles resulted in greater mediolateral sway during each phase (p < .01) and had a detrimental effect on anterior-posterior sway in phases 1 and 3. EMG data suggested more extended initial knee angles also increased EMG activity of the Tibialis Anterior (p < .001) and Bicep Femoris (p < .02) within Phases 1 and 2 to assist lift and stabilisation. SIGNIFICANCE: Findings of this study outline phase-based muscle involvement as well as the compounding effects of reduced proprioceptive input and knee angle, on difficulty of the STS transition. Such results emphasising the need to take sensory and mobility issues into consideration when designing rehabilitative programs or stimulation control systems.

Initial and subsequent therapy for newly diagnosed type 2 diabetes patients treated in primary care using data from a vendor-based electronic health record.

BACKGROUND: Diabetes is a leading cause of death and disability, and its prevalence is increasing. When diet fails, patients with type 2 diabetes mellitus (T2DM) are prescribed oral hypoglycemics for glycemic control. Few studies have explored initial use or change from initial oral hypoglycemic therapy in the primary care setting. We aimed to describe the utilization of initial oral hypoglycemics among newly diagnosed patients with diabetes from 1998-2009 and changes from initial to subsequent therapy among patients prescribed older oral hypoglycemic agents using electronic health records. METHODS: This observational cohort study used electronic health records from newly diagnosed patients with T2DM between 1 January 1998 and 31 March 2009 at two large health systems in the USA. Oral hypoglycemics included older (biguanide, sulfonylurea, and thiazolidinedione) and newer agents (incretin mimetic agents, alpha-glucosidase inhibitors, and D-phenylalanine derivatives). Multinomial regression models were fit to evaluate initial older oral hypoglycemic medication. We used incidence density sampling and conditional logistic regression models to evaluate predictors of regimen change. RESULTS: Most patients were treated from the biguanide class of oral hypoglycemics (67%), but there were differences in initial prescribing by age and race. HbA1c (Odds Ratio for HbA1c 7.0-8.9 vs < 7.0, 5.87 [95% Confidence Interval: 3.62-9.52]; Odds Ratio for HbA1c ≥ 9 vs < 7.0, 20.25 [95% Confidence Interval: 8.32-49.29] and Black people (Odds Ratio, 0.29 [95% Confidence Interval: 0.14, 0.60]) versus White people were associated with regimen change in the adjusted analysis. CONCLUSIONS: Clinical and demographic characteristics influence choice and duration of initial oral hypoglycemic treatment as well as regimen changes.

A biomechanical assessment of ergometer task specificity in elite flatwater kayakers.

The current study compared EMG, stroke force and 2D kinematics during on-ergometer and on-water kayaking. Male elite flatwater kayakers (n = 10) performed matched exercise protocols consisting of 3 min bouts at heart and stroke rates equivalent to 85% of VO2peak (assessed by prior graded incremental test). EMG data were recorded from Anterior Deltoid (AD), Triceps Brachii (TB), Latissimus Dorsi (LD) and Vastus Lateralis (VL) via wireless telemetry. Video data recorded at 50 Hz with audio triggers pre- and post-exercise facilitated synchronisation of EMG and kinematic variables. Force data were recorded via strain gauge arrays on paddle and ergometer shafts. EMG data were root mean squared (20ms window), temporally and amplitude normalised, and averaged over 10 consecutive cycles. In addition, overall muscle activity was quantified via iEMG and discrete stroke force and kinematic variables computed. Significantly greater TB and LD mean iEMG activity were recorded on-water (239 ± 15 vs. 179 ± 10 µV. s, p < 0.01 and 158 ± 12 vs. 137 ± 14 µV.s, p < 0.05, respectively), while significantly greater AD activity was recorded on-ergometer (494 ± 66 vs. 340 ± 35 µV.s, p < 0.01). Time to vertical shaft position occurred significantly earlier on-ergometer (p < 0.05). Analysis of stroke force data and EMG revealed that increased AD activity was concurrent with increased external forces applied to the paddle shaft at discrete phases of the on-ergometer stroke cycle. These external forces were associated with the ergometer loading mechanism and were not observed on- water. The current results contradict a previous published hypothesis on shoulder muscle recruitment during on-water kayaking. Key pointsWhen exercising at fixed heart and stroke rates, biomechanical differences exist between onergometer and on-water kayaking.Ergometer kayaking results in significantly greater Anterior Deltoid activity but significantly lower Triceps Brachii and Latissimus Dorsi activity, compared with on-water kayaking.The altered muscle recruitment patterns observed on-ergometer are most likely a result of additional forces associated with the ergometer loading mechanism, acting upon the paddle shaft.

Effect of Kayak Ergometer Elastic Tension on Upper Limb EMG Activity and 3D Kinematics.

Despite the prevalence of shoulder injury in kayakers, limited published research examining associated upper limb kinematics and recruitment patterns exists. Altered muscle recruitment patterns on-ergometer vs. on-water kayaking were recently reported, however, mechanisms underlying changes remain to be elucidated. The current study assessed the effect of ergometer recoil tension on upper limb recruitment and kinematics during the kayak stroke. Male kayakers (n = 10) performed 4 by 1 min on-ergometer exercise bouts at 85%VO2max at varying elastic recoil tension; EMG, stroke force and three-dimensional 3D kinematic data were recorded. While stationary recoil forces significantly increased across investigated tensions (125% increase, p < 0.001), no significant differences were detected in assessed force variables during the stroke cycle. In contrast, increasing tension induced significantly higher Anterior Deltoid (AD) activity in the latter stages (70 to 90%) of the cycle (p < 0.05). No significant differences were observed across tension levels for Triceps Brachii or Latissimus Dorsi. Kinematic analysis revealed that overhead arm movements accounted for 39 ± 16% of the cycle. Elbow angle at stroke cycle onset was 144 ± 10°; maximal elbow angle (151 ± 7°) occurred at 78 ± 10% into the cycle. All kinematic markers moved to a more anterior position as tension increased. No significant change in wrist marker elevation was observed, while elbow and shoulder marker elevations significantly increased across tension levels (p < 0.05). In conclusion, data suggested that kayakers maintained normal upper limb kinematics via additional AD recruitment despite ergometer induced recoil forces. Key pointsKayak ergometer elastic tension significantly alters Anterior Deltoid recruitment patterns.Kayakers maintain optimal arm kinematics despite changing external forces via altered shoulder muscle recruitment.Overhead arm movements account for a high proportion of the kayak stroke cycle.

A Comparison of Physiological Response to Incremental Testing on Stationary and Dynamic Rowing Ergometers.

PURPOSE: The purpose of the current study was to compare responses to graded exercise testing (GXT) on 2 popular commercial rowing ergometers. METHODS: A cohort of 23 subelite male rowers (age 20 [2] y, height 1.88 [0.06] m, body mass 82.0 [8.8] kg) performed a GXT on both stationary (Concept2 [C2]) and dynamic (RowPerfect3 [RP3]) rowing ergometers. Physiological responses including oxygen consumption (VO2), heart rate (HR), blood lactate concentration (BLa), stroke rate (SR), and minute ventilation (VE) were recorded. BLa data were plotted graphically and anaerobic threshold was identified using the Dmax method. Workload, HR, and VO2 at Dmax were interpolated. Physiological responses at maximal exercise and at Dmax were compared, along with response across a discrete range of submaximal workloads. RESULTS: At maximal exercise, no significant differences in HR, VO2, or BLa were observed (P > .05); however, VEpeak was significantly higher during RP3 tests (T = 2.943, P < .05). No significant differences in HR, VO2, or BLa at Dmax were observed (P > .05). When comparing across submaximal workloads, HR was significantly higher with the RP3 at 2 distinct workloads (210 and 240 W; P < .05), while SR was higher during RP3 testing at all workloads (F = 56.7, P < .05). When SR was fixed as a covariate, the effect of ergometer on HR response was not significant. A significant workload by ergometer interaction effect was observed for SR with higher data recorded on the RP3 (F = 3.48, P < .01). Levels of agreement for GXT-derived measures of anaerobic threshold (Dmax) were deemed unacceptable. CONCLUSIONS: These results indicate that while some differences in HR and VE response were observed between ergometers, these differences were a result of SR alterations between ergometer type. While no differences in response at Dmax were observed, the poor levels of agreement between ergometers suggests that prescription of GXT-derived threshold for training should ideally be specific to the rowing ergometer upon which the test was performed.