Clinical Scenario: Knee pathologies often require rehabilitation to address the loss of knee-extensor (KE) strength, function, and heightened pain. However, in the early stages of rehabilitation, higher loads may be contraindicated. Blood flow restriction (BFR) resistance training does not require high loads and has been used clinically to promote strength improvements in a variety of injured populations. BFR resistance training may be an effective alternative to high-intensity resistance training during early rehabilitation of knee pathologies. Clinical Question: Following a knee injury, does BFR resistance training improve KE strength and function, and reduce patient-reported pain? Summary of Key Findings: Four randomized controlled trial studies met the inclusion criteria. Each included study evaluated the use of BFR resistance training on knee pathologies and the effects on KE strength, functional outcomes, and pain compared with high- or low-load resistance training. All 4 studies reported significant improvements in KE strength, function, and pain through a variety of outcome measures, following BFR resistance training use as the treatment. Clinical Bottom Line: There is consistent evidence to support the use of BFR resistance training as a treatment intervention following knee injury and as a means to improve KE strength and function and to reduce pain. Strength of Recommendation: Grade A evidence supporting the use of BFR resistance training for improvement in KE strength and function, and the reduction of patient-reported pain following an acute or chronic knee pathology.
Matthew Zaremba, Joel Martin, and Marcie Fyock-Martin
Elizabeth Hollenczer, Angelica Esposito, and Erin M. Moore
Clinical Scenario: Due to the Female Athlete Triad (Triad) being a 3-pronged syndrome, treatments can vary depending on the symptoms that clinicians focus on. With reproductive and bone health compromised, assessment and recovery methods include monitoring menstrual regularity and dual-energy X-ray absorptiometry scans. Low levels of estrogen have demonstrated negative effects on bone mineral density (BMD). Clinical Question: Does supplemental estrogen improve BMD in athletes with Female Athlete Triad symptoms? Summary of Key Findings: Supplemental estrogen does improve BMD with estrogen patches demonstrating increased improvement compared with oral contraceptive pills. Clinical Bottom Line: Restoration of regular menstruation, improvement of BMD, and ensuring optimal energy levels is the best approach for treating Triad symptoms. Transdermal patches are a new treatment option that address both menstrual function and BMD but still require further research. Strength of Recommendation: Available studies demonstrated a level 2 evidence for supplemental estrogen (oral contraceptive pills and estrogen patches) providing improvements for bone health related to the Triad.
Adam J. Wells and Bri-ana D.I. Johnson
Context: The Dynavision D2™ Mode A test (ModeA) is a 1-minute reaction time (RT) test commonly used in sports science research and clinical rehabilitation. However, there is limited data regarding the effect of repeated testing (ie, training) or subsequent periods of no testing (ie, detraining) on test–retest reliability and RT performance. Therefore, the purpose of this study was to examine the test–retest reliability, training, and detraining effects associated with the D2™ ModeA test. Design: Repeated measures/reliability. Methods: Twenty-four recreationally active men and women completed 15 training sessions consisting of 2 ModeA tests per session (30 tests). The participants were then randomized to either 1 or 2 weeks of detraining prior to completing 15 retraining sessions (30 tests). The training and retraining periods were separated into 10 blocks for analysis (3 tests per block). The number of hits (hits) and the average RT per hit (AvgRT) within each block were used to determine RT performance. Intraclass correlation coefficients, SEM, and minimum difference were used to determine reliability. Repeated-measures analysis of variance/analysis of covariance were used to determine training and detraining effects, respectively. Results: The ModeA variables demonstrated excellent test–retest reliability (intraclass correlation coefficient2,3 > .93). Significant improvements in hits and AvgRT were noted within training blocks 1 to 5 (P < .05). No further improvements in RT performance were noted between training blocks 6 through 10. There was no effect of detraining period on RT. The RT performance was not different between blocks during retraining. Conclusions: It appears that 15 tests are necessary to overcome the training effect and establish reliable baseline performance for the ModeA test. Detraining for 1 to 2 weeks did not impact RT performance. The authors recommend that investigators and clinicians utilize the average of 3 tests when assessing RT performance using the D2 ModeA test.
Oladipo Eddo, João R. Vaz, Jaime Ludwick, Bryndan Lindsey, Joel Martin, Shane Caswell, and Nelson Cortes
Trunk modification is associated with knee abduction moment reduction in both healthy groups and individuals with knee osteoarthritis. Ambulatory-related changes in trunk kinematics have been implicated in increased trunk moment. The purpose of this study was to investigate the effect of dose-specific lateral trunk lean on trunk kinetics during ipsilateral and contralateral stance phases. Nineteen healthy participants completed 10 baseline walking trials, followed by 10 trials employing lateral trunk lean. Trunk modification magnitudes were determined based on the average baseline trunk angle. Five trials of both small and large trunk modification magnitudes were completed. Visual real-time biofeedback was projected as a line graph displaying the trunk angle during stance, and a highlighted bandwidth was designated the target range. A 1-factor repeated-measures analysis of variance or Friedman test was used to assess differences between the conditions (P < .05) in trunk dependent measures. Trunk kinetics displayed significant increases, even during modest modifications to the trunk angle. The participants experienced increased peak frontal plane trunk moment and angular impulse during ipsilateral stance. The observed increase in the peak lateral joint reaction force is suggestive of a compromised loading environment at the spine. Implementing trunk modification might result in unintended secondary changes along the kinetic chain, but further investigation is required.
Frederico Ribeiro Neto, Ramires Alsamir Tibana, Jefferson Rodrigues Dorneles, and Rodrigo Rodrigues Gomes Costa
Context: Paracanoeing is one of the adapted sports eligible for different motor impairments. The acute:chronic workload ratio (ACWR) is an index between acute and chronic training workload. However, no studies have analyzed this variable in paracanoeing, relating it with training recovery markers. Objective: This study aimed to quantify the internal (session rating of perceived exertion) and external (distance traveled and total training time) training workloads in 4 experienced paracanoe athletes over 9 months and 5 canoeing events. Design: Cross-sectional study. Setting: Rehabilitation Hospital Network, Paralympic Program. Participants: Four experienced paracanoe athletes participated in 36 weeks of training for 5 events. Main Outcomes Measures: The daily and weekly training workload, monotony, ACWR, distance, and total training time were described for all the training phases. The perceived recovery status scale (PRS) and medicine ball throw (MBT) were used to quantify recovery. Results: The average daily and weekly training workload varied from 213.1 to 239.3 and 767.3 to 1036.8 arbitrary units, respectively. Average ACWR results ranged from 0.96 to 1.10 in the 4 athletes, findings that were outside the safety zone in 38% of the training weeks. All the correlations between MBT and PRS were classified as weak (ρ between .20 and .39, P > .05). ACWR showed a very weak correlation with MBT and moderately and highly significant correlations with PRS in 2 athletes, respectively. Conclusions: The training workloads of 4 paracanoe athletes may serve as a comparison with other periodization models. Pretraining recovery assessments (MBT and PRS) exhibited a low, nonsignificant correlation. However, ACWR correlated significantly with PRS in 2 athletes and might be a suitable tool for daily training adjustments.
Raki Kawama, Masamichi Okudaira, Hirohiko Maemura, and Satoru Tanigawa
Context: Strength deficits of the hamstrings following sports injuries decrease athletic performance and increase the risk of injury recurrence. Previous studies have shown a high correlation between the muscular strength during hip-extension and knee-flexion and total muscle size of the hamstrings. However, it remains unclear which region of the individual hamstring muscles is closely associated with muscular strength. Objective: To investigate the relationship between the size of each region of the individual hamstring muscles and muscular strength during hip extension and knee flexion. Design: Within-subject repeated measures. Setting: University laboratory. Participants: Twenty healthy young male volunteers who regularly engaged in sports activities. Outcome Measures: Anatomical cross-sectional areas were acquired from the proximal, middle, and distal regions of the biceps femoris long head, biceps femoris short head, semitendinosus, and semimembranosus. Hip-extension and knee-flexion strength were measured during maximal voluntary isometric and concentric contractions (angular velocities of 60°/s and 180°/s). Results: The anatomical cross-sectional area of the distal regions in biceps femoris long head (r = .525–.642) and semitendinosus (r = .567) were significantly correlated with hip-extension strength under all conditions and only at an angular velocity of 180°/s, respectively. Meanwhile, anatomical cross-sectional areas of the distal regions in biceps femoris short head (r = .587–.684) and semimembranosus (r = .569–.576) were closely associated with knee-flexion strength under all conditions. Conclusion: These results suggest that muscle size in the distal regions of biceps femoris long head and semitendinosus greatly contributes to the production of hip-extension strength, whereas that of biceps femoris short head and semimembranosus significantly contributes to the generation of knee-flexion strength. These findings could be useful for designing training and rehabilitation programs to efficiently improve strength deficits following sports injuries such as strain injury and anterior cruciate ligament tears.
Megan M. Byrd, Anthony P. Kontos, Shawn R. Eagle, and Samuel Zizzi
This study used an exploratory mixed-method sequential design to examine anger, impulsivity, and anxiety following sport-related concussions (SRC). Ten college athletes (M = 20.10 years, SD = 2.92) completed four measures 1–10 days postconcussion (Visit 1) and 11–20 days postconcussion (Visit 2). At return to play or 30 days postconcussion, the athletes completed a semistructured interview (follow-up) to assess their lived experiences of the emotional sequelae of concussions. All participants indicated experiencing some level of anxiety at Visit 1, with half the participants scoring above the measure’s threshold for probable clinical diagnosis of anxiety. The results found a significant decrease in symptoms and anxiety at Visit 2. Inductive coding revealed frustration, irritability, impulsive behavior, and fear of the unknown as themes pertaining to athletes’ experiences. The findings highlight the need for sports medicine and sport psychology professionals to provide athletes with information to normalize their emotional responses during recovery.
Francisco Javier Núñez, Carlos Galiano, Alejandro Muñoz-López, and Pablo Floria
High intraset variability has been considered as a potential aid in the treatment of tendinopathy by producing forces in variable and unpredictable contexts that allow the athlete to return to sport pain free. The aim of this study was to compare the intraset variability in force profiles between different rotational inertia devices (RIDs) during concentric and eccentric (ECC) phases of movement and between different moments of inertia. Thirty-nine men performed a half-squat incremental test on 2 different RIDs: a horizontal cylinder and a vertical cone-shaped axis. Intraset variabilities in vertical force and velocity were analyzed using average coefficients of variation. RID squat exercise produced force intraset variability. The ECC phase of the movement showed more intraset variability in force output than the concentric phase. ECC vertical cone-shaped shaft showed a higher intraset variability in force than ECC horizontal cylinder-shaped shaft. This study demonstrated that using an RID to provide resistance in squat training of athletes produced a high intraset variability in the application of force.
Jillian L. Hawkins and Clare E. Milner
Differences in walking biomechanics between groups or conditions should be greater than the measurement error to be considered meaningful. Reliability and minimum detectable differences (MDDs) have not been determined for lower-extremity angles and moments during walking within a session, as needed for interpreting differences in cross-sectional studies. Thus, the purpose of this study was to determine within-session reliability and MDDs for peak ankle, knee, and hip angles and moments during walking. Three-dimensional gait analysis was used to record walking at 1.25 m/s (±5%) in 18 men, 18–50 years of age. Peak angles and moments were calculated for 2 sets of 3 trials. Intraclass correlation coefficients (3, 3) were used to determine within-session reliability. In addition, MDDs were calculated. Within-session reliability was good to excellent for all variables. The MDDs ranged from 0.9° to 3.6° for joint angles and 0.06 to 0.15 N·m/kg for joint moments. Within-session reliability for peak ankle, knee, and hip angles and moments was better than the between-session reliability reported previously. Overall, our MDDs were similar or smaller than those previously reported for between-session reliability. The authors recommend using these MDDs to aid in the interpretation of cross-sectional comparisons of lower-extremity biomechanics during walking in healthy men.
Jacqueline Martins Patatas, Jens De Rycke, Veerle De Bosscher, and Rafael Lima Kons
The literature suggests that the current athlete development models do not reflect the multifaceted developmental pathways in Paralympic sport. This study aimed to analyze how parasport athletes progress through developmental phases of an athletic career pathway by comparing differences in their trajectories based on the nature of the impairment (acquired or congenital), age, and sex. A total of 345 para-athletes representing 15 sports completed an online survey. Results showed that the developmental phases for athletes with acquired impairment are of shorter duration, taking 4.5 years to progress from the attraction to the elite phase, while athletes with congenital impairment take 6 years. Athletes with congenital impairment start in parasport approximately 8 years younger and win medals in international competitions 7 years earlier than athletes with acquired impairment. Insights gathered in this study have the potential to enhance further thinking toward the genesis of specific models of para-athlete development.