Acute aerobic exercise-conditioned serum reduces colon cancer cell proliferation in vitro through interleukin-6-induced regulation of DNA damage.

Epidemiological evidence shows that regular physical activity is associated with reduced risk of primary and recurrent colon cancer. However, the underlying mechanisms of action are poorly understood. We evaluated the effects of stimulating a human colon cancer cell line (LoVo) with human serum collected before and after an acute exercise bout vs nonexercise control serum on cancer cell proliferation. We also measured exercise-induced changes in serum cytokines and intracellular protein expression to explore potential biological mechanisms. Blood samples were collected from 16 men with lifestyle risk factors for colon cancer (age ≥50 years; body mass index ≥25 kg/m2 ; physically inactive) before and immediately after an acute bout of moderate-intensity aerobic interval exercise (6 × 5 minutes intervals at 60% heart rate reserve) and a nonexercise control condition. Stimulating LoVo cells with serum obtained immediately after exercise reduced cancer cell proliferation compared to control (-5.7%; P = .002). This was accompanied by a decrease in LoVo cell γ-H2AX expression (-24.6%; P = .029), indicating a reduction in DNA damage. Acute exercise also increased serum IL-6 (24.6%, P = .002). Furthermore, stimulating LoVo cells with recombinant IL-6 reduced γ-H2AX expression (ß = -22.7%; P < .001) and cell proliferation (ß = -5.3%; P < .001) in a linear dose-dependent manner, mimicking the effect of exercise. These findings suggest that the systemic responses to acute aerobic exercise inhibit colon cancer cell proliferation in vitro, and this may be driven by IL-6-induced regulation of DNA damage and repair. This mechanism of action may partly underlie epidemiological associations linking regular physical activity with reduced colon cancer risk.

Relationships Between Eccentric and Concentric Knee Strength Capacities and Maximal Linear Deceleration Ability in Male Academy Soccer Players.

ABSTRACT: Harper, DJ, Jordan, AR, and Kiely, J. Relationships between eccentric and concentric knee strength capacities and maximal linear deceleration ability in male academy soccer players. J Strength Cond Res 35(2): 465-472, 2021-The purpose of this study was to investigate the relationships between maximal linear deceleration ability, and knee flexor (KF) and knee extensor (KE) strength. Fourteen male academy soccer players completed a 30-m linear sprint, a maximal linear deceleration test, and eccentric and concentric KF and KE contractions in both dominant leg (DL) and nondominant leg (NDL) at slower (60°·s-1) and faster (180°·s-1) angular velocities on an isokinetic dynamometer. Maximal linear deceleration ability was evaluated using distance-to-stop (DEC-DTS) and time-to-stop (DEC-TTS), with isokinetic peak torque representing KF and KE strength capacity. Relationships were established using Pearson's correlation coefficients (r) with magnitude-based inferences used to describe the uncertainty in the correlation. Both concentric KE and KF strength at 180°·s-1 in the NDL had the highest correlations with deceleration ability (r = -0.76 and r = -0.78, respectively). In the DL, concentric KE and KF strength at 180°·s-1 also had very likely large correlations with deceleration ability (r = -0.54 and -0.55, respectively). All correlations between eccentric KF strength and deceleration ability were unclear. At 180°·s-1, correlations between eccentric KE strength and deceleration ability were also unclear; however, at 60°·s-1, both DL (r = -0.63 to -0.64) and NDL (r = -0.54 to -0.55) had very likely large correlations with deceleration ability. These findings provide novel insights into the unilateral KF and KE strength capacities underpinning the ability to decelerate rapidly from high-sprint velocities.

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 (ß = -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.

Validity of various portable devices to measure sit-to-stand velocity and power in older adults.

BACKGROUND: Movement velocity and power in a single STS are related to functional performance in older adults. Identifying accessible tools that provide valid measures of STS velocity/power would allow practitioners to evaluate physical function in clinical settings where time, space and finances are limited. RESEARCH QUESTION: Does a linear position transducer (LPT), iPhone application (App), and inertial measurement unit (IMU) obtain valid measurements of velocity and power during a single STS compared with 3D motion capture? METHODS: Twenty-seven community-dwelling older adults aged ≥60 years completed a single STS test with mean velocity and power simultaneously measured with 3D motion capture, an LPT, IMU and App. Acceptable validity was established if the Pearson correlation coefficient (r) was very high (≥0.7) and bias as a standardised effect size (ES) was small (<0.6). The relationship between STS velocity/power and 30s chair STS performance was also evaluated. RESULTS: Measures of STS velocity obtained by the LPT (r = 0.94, ES = -0.21) and App (r = 0.89, ES = -0.19) were very highly valid when compared to 3D motion capture, and were very strongly related to 30s STS performance (r ≥0.74). The LPT (r = 0.87, ES = 0.13) and App (r = 0.74, ES = -0.12) also showed very high correlations and negligible bias for measuring STS power. Data collected by the IMU failed to meet our pre-determined threshold of acceptable validity for STS velocity (r = 0.72, ES = 1.00) or power (r = 0.61, ES = 0.34). SIGNIFICANCE: The LPT and iPhone App, but not the IMU, are valid tools for measuring STS velocity and power in community-dwelling older adults. Clinicians can use STS velocity obtained by either the LPT or App as a simple and valid proxy for functional status, which could help identify patients at high-risk of incident disability.

Three-curve rocker-soled shoes and gait adaptations to intermittent claudication pain: A randomised crossover trial.

BACKGROUND: Intermittent claudication (IC) is a symptom of peripheral arterial disease where a cramp-like leg pain is exhibited during walking, which affects gait and limits walking distance. Specifically-designed rocker-soled shoes were purported to mechanically unload the calf musculature and increase walking distances until IC pain. RESEARCH QUESTIONS: Do three-curve rocker-soled shoes increase walking distance and what are the biomechanical differences during pain-free walking and IC pain-induced walking, when compared with control shoes? METHODS: Following NHS ethical approval, 31 individuals with claudication (age 69 ± 10 years, stature 1.7 ± 0.9 m, mass 83.2 ± 16.2 kg, ankle-brachial pressure index 0.55 ± 0.14) were randomised in this cross-over trial. Gait parameters whilst walking with rocker-soled shoes were compared with control shoes at three intervals of pain-free walking, at onset of IC pain (initial claudication distance) and when IC intensifies and prevents them walking any further (absolute claudication distance). Two-way repeated measures ANOVA were performed on gait variables. RESULTS: When compared with control shoes, rocker-soled shoes reduced ankle power generation (mean 2.1 vs 1.6 W/kg, respectively; p = 0.006) and altered sagittal kinematics of the hip, knee and ankle. However, this did not translate to a significant increase in initial (138 m vs 146 m, respectively) or absolute (373 m vs 406 m, respectively) claudication distances. In response to IC pain, similar adaptations in temporal-spatial parameters and the sagittal kinematics were observed between the shoe types. SIGNIFICANCE: The three-curved rocker shoes, in their current design, do not augment gait sufficiently to enhance walking distance, when compared with control shoes, and therefore cannot be recommended for the intermittent claudication population. Clinical Reg No. (ClinicalTrials.gov): NCT02505503.

Unloading shoes for intermittent claudication: a randomised crossover trial.

BACKGROUND: The purpose of this study was to assess the functional effects and acceptability of rocker-soled shoes that were designed to relatively "unload" the calf muscles during walking in people with calf claudication due to peripheral arterial disease. METHODS: In this randomised AB/BA crossover trial, participants completed two assessment visits up to two weeks apart. At each visit, participants completed walking tests whilst wearing the unloading shoes or visually-similar control shoes. At the end of the second visit, participants were given either the unloading or control shoes to use in their home environment for 2 weeks, with the instruction to wear them for at least 4 h every day. The primary outcome was 6-min walk distance. We also assessed pain-free walking distance and gait biomechanical variables during usual-pace walking, adverse events, and participants' opinions about the shoes. Data for continuous outcomes are presented as mean difference between conditions with corresponding 95% confidence interval. RESULTS: Thirty-four participants (27 males, mean age 68 years, mean ankle-brachial index 0.54) completed both assessment visits. On average, the 6-min walk distance was 11 m greater when participants wore the control shoes (95% CI -5 to 26), whereas mean pain-free walking distance was 7 m greater in the unloading shoes (95% CI -17 to 32). Neither of these differences were statistically significant (p = 0.18 and p = 0.55, respectively). This was despite the unloading shoes reducing peak ankle plantarflexion moment (mean difference 0.2 Nm/kg, 95% CI 0.0 to 0.3) and peak ankle power generation (mean difference 0.6 W/kg, 95% CI 0.2 to 1.0) during pain-free walking. The survey and interview data was mixed, with no clear differences between the unloading and control shoes. CONCLUSIONS: Shoes with modified soles to relatively unload the calf muscles during walking conferred no substantial acute functional benefit over control shoes. TRIAL REGISTRATION: Clinicaltrials.gov, Trial Registration Number: NCT02505503 , First registered 22 July 2015.

Kinematics and neuromuscular recruitment during vertical treadmill exercise.

The vertical treadmill (VertiRun) is an unresearched, partial weight-bearing exercise mode for lower limb rehabilitation. The user undertakes a "running-like" action whilst body weight is supported by a bench and the limb is drawn downwards against overhanging resistance cables on a vertically hung nonmotorised treadmill. This study sought to describe the kinematics and neuromuscular recruitment during VertiRun exercise in the supine, 40°, and 70° postures. Twenty-one healthy male participants (age, 25±7 years; stature, 1.79±0.07 m; body mass, 77.7±8.8 kg) volunteered for sagittal plane kinematic analysis of the ankle, knee and hip and electromyography of lower limb musculature in all three postures. Results indicated similar kinematic and neuromuscular profiles in the 40° and 70° postures which differed from the supine. Regardless of posture, a basic movement pattern was observed where the hamstrings and gastrocnemius muscles were active to extend the hip, flex the knee, plantarflex the ankle and draw the leg down the treadmill belt in the contact phase. The rectus femoris and tibialis anterior were active to flex the hip and knee, and dorsiflex the ankle to draw the leg upwards during the swing phase. The vasti muscles were not active during VertiRun exercise. The VertiRun demonstrated similar kinematic and neuro-muscular patterns to overground gait, allows workload progression based on effort and posture changes, and is a low-impact exercise mode that could maintain physical fitness without loading injured tissues. This study suggests that the VertiRun could supplement rehabilitation programmes for lower-limb injuries.

Computerized dynamic posturography in the objective assessment of balance in patients with intermittent claudication.

One-third of all elderly patients fall each year and impaired balance has been recognized as a specific risk factor. Intermittent claudication is common among the elderly population, affecting approximately 5% of the population over the age of 50. The aim of this proof-of-concept study was to assess the prevalence of impaired balance among elderly claudicants and to assess each patient's insight into their own risk of falling. A total of 58 claudicants (45 men), median age of 70 (interquartile range = 65-73) years, underwent objective balance assessment by using computerized dynamic posturography. As compared with 195 (5%) historic controls, 24 (41%) of the claudicants demonstrated abnormal balance when the Sensory Organization Test (SOT) was used. Vestibular dysfunction occurred in 52% of the claudicants. Abnormalities including somatosensory (22%), visual function (17%), and preferential reliance on inaccurate visual cues (17%) occurred less often. Prolonged Motor Control Test latency times were uncommon (n = 13) and were in most cases evenly distributed between those with normal (n = 7) and abnormal (n = 6) composite SOT scores. There was a significant difference in history of falling between claudicants with abnormal and normal SOT scores (p = 0.003), with a higher number of patients with abnormal SOT having experienced falling in the past year. However, no correlation between fear of falling and composite SOT score was found (Spearman rank correlation, r = 0.124; p = 0.381). Impaired balance, particularly secondary to vestibular problems, is very common among claudicants and may predispose to a high incidence of falls. Claudicants with abnormal balance are more likely to have a history of falls but not a fear of falling, thus potentially rendering these patients to be at a greater risk.