A Review of Biophysical Differences between Aquatic and Land-Based Exercise

Four of the most popular modes of aquatic exercise are deep-water (DW) exercise, shallow water (SW) exercise, water calisthenics (WC), and underwater treadmill (UT) exercise. The mechanical requirements of each aquatic exercise mode may elicit different physiological and biomechanical responses. The purpose of this descriptive literature review was to evaluate some biophysical differences between aquatic and land-based exercises. The biophysical variables included oxygen consumption (VO2), heart rate (HR), rating of perceived exertion (RPE), stride length, stride frequency, pain, and measures of functional gain. Based on the studies reviewed, when compared to similar land-based exercises, VO2 and HR maximum values were lower during DW and SW exercise, but, depending on water depth and exercise performed, may be greater during WC and UT exercise. RPE during DW exercise was generally similar to land exercise during max effort. Stride frequency tended to be lower for all four aquatic exercises, relative to on-land counterparts. Pain levels tended to be similar between WC and land exercise, yet may decrease after UT exercise

Effect of Surface Stability on Core Muscle Activity for Dynamic Resistance Exercises

To compare core muscle activity during resistance exercises performed on stable ground vs. the BOSU Balance Trainer. Methods: Twelve trained men performed the back squat, dead lift, overhead press, and curl lifts. The activity of the rectus abdominis, external oblique abdominis, transversus abdominis/internal oblique abdominis, and erector spinae muscles was assessed. Subjects performed each lift under three separate conditions including standing on stable ground with 50% of a 1-RM, standing on a BOSU Balance Trainer with 50% of a 1-RM, and standing on stable ground with 75% of a 1-RM. Results: Significant differences were noted between the stable 75% of 1-RM and BOSU 50% of 1-RM conditions for the rectus abdominis during the overhead press and transversus abdominis/internal oblique abdominis during the overhead press and curl (P \u3c .05). Conversely, there were no significant differences between the stable 75% of 1-RM and BOSU 50% of 1-RM conditions for the external obliques and erector spinae across all lifts examined. Furthermore, there were no significant differences between the BOSU 50% of 1-RM and stable 50% of 1-RM conditions across all muscles and lifts examined. Conclusions: The current study did not demonstrate any advantage in utilizing the BOSU Balance Trainer. Therefore, fitness trainers should be advised that each of the aforementioned lifts can be performed while standing on stable ground without losing the potential core muscle training benefits

Effect of Short-Term Failure Versus Nonfailure Training on Lower Body Muscular Endurance

This study compared failure versus nonfailure training with equated intensity and volume on lower body muscular endurance in trained men. Methods: Each subject performed one lower body workout per week for 6 weeks; the Failure group performed 3 sets of the squat, leg curl, and leg extension exercises to the point of voluntary exhaustion, while the Nonfailure group performed 4 sets for each of these exercises, but with a submaximal number of repetitions that did not allow failure to occur on any set. All subjects performed a pre- and postintervention muscular endurance test that involved 3 sets each for the squat, leg curl, and leg extension exercises. Blood lactate concentration (BL) was assessed before, and at 5 and 10 minutes following the test. Heart rate (HR) was assessed before the test, following the last set of each exercise, and for 10 minutes following the test. Results: Both groups demonstrated significant increases in total work (P \u3c .0001) for the postintervention test, with no significant differences between the groups (P = .882). When comparing the pre- and postintervention tests, BL and HR were not significantly different at any time point (P \u3e .05). Conclusions: These results indicate that when intensity and volume are equated, failure or nonfailure training results in similar gains in lower body muscular endurance. Therefore, when assessed over relatively short training cycles, the total volume of training might be more important versus whether sets are performed to failure for muscular endurance-related adaptations

A Mixed-Methods Approach to Evaluating the Internal Validity of the Reactive Strength Index

The reactive capacity of the muscle-tendon complex is commonly assessed using the reactive strength index (RSI). Conventionally, the RSI is a ratio of rebound jump height to ground contact time in depth jumping. Several assumptions regarding the linear mechanics acting through the whole-body center of gravity may threaten the internal validity of computation and interpretation of RSI scores. First, it is common for rebound jump height to be predicted from rebound jump flight time. This assumes that the angular positioning of body segments is equivalent at the time instances of rebound jump take-off and landing. Prior literature supports a mixed-methods approach for computing the RSI that is void of this assumption. The mixed-methods approach gives a more valid estimation of rebound jump height. In this approach, rebound jump height is estimated from rebound jump take-off velocity of the whole-body center of mass. This is accomplished by subtracting an estimate of impact velocity, acquired using videography, from change in whole-body center of mass velocity estimated from integrated vertical ground reaction force data. Second, it is often assumed that vertical displacement of the whole-body center of mass during the drop phase of the depth jump is predicted perfectly from the height of the platform used to perform the drop. This assumption may affect the internal validity of comparing RSI scores across individuals and within individuals performing depth jumps from varied heights. The purpose of the present study was to investigate the internal validity of RSI scores computed using the conventional approach and impact velocity variability, which may affect the interpretation of RSI scores. Seventy physically active young adults performed depth jumps from drop heights of 0.51, 0.66, and 0.81 m. RSI was computed using the conventional approach and a mixed-methods approach featuring the use of 2-dimensional videography, body segment parameters, and force platform dynamometry. The two computational methods were compared using linear regression performed on data from each drop height. In addition, a 2 (computational method) by 3 (drop height) Analysis of Variance (ANOVA) was performed to evaluate for main effects and interactions in RSI data. Multiple one sample t-tests were performed to compare estimated and theoretical impact velocities. The ANOVA revealed no main effect or interactions between computational approaches (p = 0.467–0.938). Linear regression revealed moderately strong associations between RSI scores computed using the conventional and mixed-methods approaches (R2 = 0.685–0.741). Moreover, linear regressions revealed that the conventional approach tends to overestimate the mixed methods approach for RSI scores below 1.0 and underestimate the mixed methods approach for RSI scores above 1.0. Lastly, estimated impact velocities were observed to be as much as 13% lower versus theoretical (p \u3c 0.001). Researchers with access to motion capture and force platform technology may consider using a mixed-methods approach for computing the RSI, which likely maximizes the internal validity of scores. In addition, results suggest for practitioners to practice caution when comparing conventional RSI scores across individuals

Effect of Short-Term Failure Versus Nonfailure Training on Lower Body Muscular Endurance

This study compared failure versus nonfailure training with equated intensity and volume on lower body muscular endurance in trained men. Methods: Each subject performed one lower body workout per week for 6 weeks; the Failure group performed 3 sets of the squat, leg curl, and leg extension exercises to the point of voluntary exhaustion, while the Nonfailure group performed 4 sets for each of these exercises, but with a submaximal number of repetitions that did not allow failure to occur on any set. All subjects performed a pre- and postintervention muscular endurance test that involved 3 sets each for the squat, leg curl, and leg extension exercises. Blood lactate concentration (BL) was assessed before, and at 5 and 10 minutes following the test. Heart rate (HR) was assessed before the test, following the last set of each exercise, and for 10 minutes following the test. Results: Both groups demonstrated significant increases in total work (P \u3c .0001) for the postintervention test, with no significant differences between the groups (P = .882). When comparing the pre- and postintervention tests, BL and HR were not significantly different at any time point (P \u3e .05). Conclusions: These results indicate that when intensity and volume are equated, failure or nonfailure training results in similar gains in lower body muscular endurance. Therefore, when assessed over relatively short training cycles, the total volume of training might be more important versus whether sets are performed to failure for muscular endurance-related adaptations

A systematic review and meta-analysis comparing the effect of aquatic and land exercise on dynamic balance in older adults

Publisher's version (útgefin grein)Abstract Background: Balance impairments are the leading causes of falls in older adults. Aquatic-based exercises have been broadly practiced as an alternative to land-based exercises; however, the effects on dynamic balance have not been comprehensively reviewed and compared to land exercises. Thus, the purpose of this systematic review and meta-analysis was to compare the effectiveness of aquatic exercises (AE) to land exercises (LE) on dynamic balance in older adults. Methods: Electronic databases (PubMed, MEDLINE, CINAHL, SPORTDiscus, psycINFO), from inception to November 2019, were searched. Studies met the following eligibility criteria: Randomized controlled trials, English language, older adults aged 65 years or older, a minimum of one AE and LE group, at least one assessment for dynamic balance. For the meta-analysis, the effect sizes of dynamic balance outcomes were calculated using a standardized mean difference (SMD) and a 95% confidence interval (CI). Results: A total of 11 trials met the inclusion criteria, and 10 studies were eligible for the meta-analysis. The meta-analysis presented that older adults in AE groups demonstrated comparable enhancements in dynamic steady-state balance (SMD =−0.24; 95% CI,−.81 to .34), proactive balance (SMD =−0.21; 95% CI,−.59 to .17), and balance test batteries (SMD =−0.24; 95% CI,−.50 to .03) compared with those in LE groups. Conclusions: AE and LE have comparable impacts on dynamic balance in older adults aged 65 years or older. Thus, this review provides evidence that AE can be utilized as a reasonable alternative to LE to improve dynamic balance and possibly reduce the risk of falls.Peer reviewe

The Relationship of Residence to Academic Performance in NCAA Division I Freshman Athletes

Numerous studies have been completed examining academic ability of student athletes. Since the mid 1980s, the NCAA has emphasized the importance of academics and mandated more stringent requirements for participation in intercollegiate athletics. These initial-eligibility standards have been successful in increasing overall graduation rates of student-athletes, but a number of concerns remain. The purpose of this study was to determine if a NCAA Division-I freshman student athlete’s place of residence on campus, as opposed to off campus, during his/her freshman year had a statistically significant relationship to academic performance. The participants of this study (N = 205) were surveyed individually to determine their place of residence and preference of residence during their freshman year. Academic performance at the end of the freshman year was obtained via the school’s database of academic records (Access Banner). Based on the results of this study, it was concluded that living in an on campus or off campus environment had no statistical relationship with how the NCAA D-I freshman student athletes performed academically. There were however, significant differences between gender. The findings warrant further discussion and continued research

Which Exercise Interventions Can Most Effectively Improve Reactive Balance in Older Adults? A Systematic Review and Network Meta-Analysis

Background: Reactive balance is the last line of defense to prevent a fall when the body loses stability, and beneficial effects of various exercise-based interventions on reactive balance in older adults have been reported. However, their pooled evidence on the relative effects has yet to be described. Objective: To review and evaluate the comparative effectiveness of various exercise-based interventions on reactive balance in older adults. Methods: Nine electronic databases and reference lists were searched from inception to August 2021. Eligibility criteria according to PICOS criteria were as follows: (1) population: older adults with the mean age of 65 years or above; (2) intervention and comparison: at least two distinct exercise interventions or one exercise intervention with no-exercise controlled intervention (NE) compared in each trial; (3) outcome: at least one measure of reactive balance; (4) study: randomized controlled trial. The main network meta-analysis was performed on data from the entire older adult population, involving all clinical conditions as well as healthy older adults. Subgroup analyses stratified by characteristics of participants (healthy only) and reactive balance outcomes (simulated slip or trip while walking, simulated forward falls, being pushed or pulled, and moveable platform) were also conducted. Results: Thirty-nine RCTs (n = 1388) investigating 17 different types of exercise interventions were included in the network meta-analysis. Reactive balance training as a single intervention presented the highest probability (surface under the cumulative ranking (SUCRA) score) of being the best intervention for improving reactive balance and the greatest relative effects vs. NE in the entire sample involving all clinical conditions [SUCRA = 0.9; mean difference (95% Credible Interval): 2.7 (1.0 to 4.3)]. The results were not affected by characteristics of participants (i.e., healthy older adults only) or reactive balance outcomes. Summary/Conclusion: The findings from the NMA suggest that a task-specific reactive balance exercise could be the optimal intervention for improving reactive balance in older adults, and power training can be considered as a secondary training exercise

The influence of oblique-angle forced exercise in surgically destabilized stifle joints is synergistic with bone, but antagonistic with cartilage in an ovine model of osteoarthritis

Large animal models of osteoarthritis are a necessary testing ground for FDA approval of human medicine applications. Sheep models have advantages over other available large animals, but development and progression of osteoarthritis in sheep is exceedingly slow, which handicaps progress in development of potential treatments. We combined oblique angle forced exercise to increase stress on the stifle, with surgical destabilization to hasten the development of osteoarthritis in ewes. Methods for early detection of clinical signs included radiography, urine, and serum biomarker assays and gait analysis and ex vivo we used microcomputed tomography and macroscopic joint analysis. Our model was able to produce clinically detectable signs of osteoarthritis in a relatively short period (14 weeks). Changes in bone were highly correlated between microcomputed tomography and radiographic analysis and changes in cartilage correlated well between urinary glycosaminoglycan levels and serum aggrecanase analyses. Exercise improved the negative effects of destabilization in bone but exacerbated the negative effects of destabilization in cartilage. These observations suggest that we may need to consider treatments for bone and cartilage separately. These results represent an improved large animal model of osteoarthritis with rapid onset of disease and superior detection of bone and soft tissue changes