Validity of diagnostic ultrasound as a measure of delayed onset muscle soreness

Influence of Structured Medium- and Long-Chain Triglycerides on Muscular Recovery Following Damaging Resistance Exercise

Background/Objectives: Structured medium- and long-chain triglycerides (sMLCT) may be a superior vehicle for medium-chain fatty acid delivery to peripheral tissues, such as skeletal muscle. Limited information is available concerning the effect of sMLCT on muscular performance or recovery after a muscle-damaging exercise protocol. The purpose of this study was to establish the effect of a novel formulation of sMLCT on muscular performance and recovery. Methods: Forty female adults (mean ± SD age = 22 ± 3 years; body mass index = 23.5 ± 3.4 kg/m2) were randomized into one of two study groups, placebo control [CON; n = 20] or sMLCT [n = 20], and completed five total visits to the laboratory. The baseline (i.e., pre-exercise) assessments of muscle performance, size, and soreness were compared to assessments immediately following exercise and 24, 48, and 72 h post-exercise. Results: No statistically significant condition × time interactions were noted for strength outcomes, although trends for condition × time interactions were present for torque over 25 ms (p = 0.06) and peak torque (p = 0.05). Similarly, no condition x time interactions were present for ultrasound echo intensity, the subjective ratings of soreness and pain, thigh circumference, leg volume, and vertical jump performance. Conclusions: Within the context of the current study, the ingestion of sMLCT did not significantly influence the rate of muscle strength recovery following muscle damaging resistance exercise.

Enhanced physical performance, attention, and mood states after a nap opportunity following a sleep restriction night in female athletes: A randomized controlled trial

This study examined the effects of two nap durations (40 minutes (N40) and 90 minutes (N90)) on physical performance, sleepiness, attention, mood states (Profile of Mood States, POMS), perceived exertion (RPE), pain perception (PP), recovery (PRS), and delayed onset muscle soreness (DOMS) in well-trained women. Fourteen female boxers underwent the digit cancellation test, POMS, and the 5-meter shuttle run test (5mSRT) under no-nap (N0), N40, and N90 conditions after either normal sleep (NSN) or sleep restriction (SRN). RPE and PP were assessed immediately post-5mSRT, while PRS and DOMS were recorded at 5 min and 24 h post-5mSRT. Total distance (TD) and higher distance (HD) were better in N40 and N90 after NSN compared to SRN (p < 0.05). Fatigue index (FI) was lower in N40 and N90 than in N0, and lower in N90 than N40 (p < 0.05). PRS improved and RPE, DOMS, and PP decreased significantly after N40 and N90 compared to N0, with N90 showing greater benefits (p < 0.05). Total POMS scores were better after N40 and N90 than N0, with N90 outperforming N40 (p < 0.05). Overall, N90 provided greater benefits than N40 in enhancing physical performance, attention, recovery, and mood, while reducing exertion, pain, and soreness after both NSN and SRN.

To Nap or Not to Nap? A Systematic Review Evaluating Napping Behavior in Athletes and the Impact on Various Measures of Athletic Performance

PURPOSE

The objective of this systematic review was to 1) determine how studies evaluated napping behavior in athletes (frequency, duration, timing and measurement); 2) explore how napping impacted physical performance, cognitive performance, perceptual measures (eg, fatigue, muscle soreness, sleepiness and alertness), psychological state and night-time sleep in athletes.

METHODS

Five bibliographic databases were searched from database inception to 11 August 2020. Observational and experimental studies comprising able-bodied athletes (mean age ≥12 years), published in English, in peer-reviewed journal papers were included. The Downs and Black Quality Assessment Checklist was used for quality appraisal.

RESULTS

Thirty-seven studies were identified of moderate quality. Most studies did not include consistent information regarding nap frequency, duration, and timing. Napping may be beneficial for a range of outcomes that benefit athletes (eg, physical and cognitive performance, perceptual measures, psychological state and night-time sleep). In addition, napping presents athletes with the opportunity to supplement their night-time sleep without compromising sleep quality.

CONCLUSION

Athletes may consider napping between 20 to 90 min in duration and between 13:00 and 16:00 hours. Finally, athletes should allow 30 min to reduce sleep inertia prior to training or competition to obtain better performance outcomes. Future studies should include comprehensive recordings of nap duration and quality, and consider using sleep over a 24 hour period (daytime naps and night-time sleep period), specifically using objective methods of sleep assessment (eg, polysomnography/actigraphy).

A 90 min Daytime Nap Opportunity Is Better Than 40 min for Cognitive and Physical Performance

This study examined the effects of different nap durations on attention and physical performance as well as mood states, sleepiness, perceived exertion (RPE), recovery (PRS), and muscle soreness (DOMS) in trained men. Fourteen amateur team sport players (age: 20.3 ± 3.0 years, height: 173.1 ± 6.7 cm, body-mass: 68.1 ± 6.6 kg) performed a maximal voluntary isometric contraction (MVIC) test, 5-m shuttle run, and the digit-cancellation (i.e., attention) test after a no-nap (N0) and 40-min (N40) and 90-min (N90) of nap opportunities. Subjective measurement of mood states, RPE, PRS and DOMS were determined. Compared to N0, both nap durations enhanced attention, MVIC, total distance (TD), and higher distance (HD) (p < 0.001), with a higher gain after N90 compared to N40 for attention (Δ = +3), MVIC (Δ = +30 N) and TD (Δ = +35 m) (p < 0.001). Total mood scores were better after N40 and N90 compared to N0 (p < 0.05), with lower scores after N90 compared to N40 (p < 0.05). DOMS and RPE scores were significantly lower and PRS was significantly higher after N40 and N90 compared to N0 and after N90 compared to N40 (p < 0.05). Although both nap opportunity durations were beneficial, N90 was better than N40 for improving physical performances and attention as well as the perception of recovery, reducing fatigue perception, muscle soreness, and negative mood states.

Exertional Rhabdomyolysis in a 21-Year-Old Healthy Woman: A Case Report

McKay, BD, Yeo, NM, Jenkins, NDM, Miramonti, AA, and Cramer, JT. Exertional rhabdomyolysis in a 21-year-old healthy woman: a case report. J Strength Cond Res 31(5): 1403-1410, 2017-The optimal resistance training program to elicit muscle hypertrophy has been recently debated and researched. Although 3 sets of 10 repetitions at 70-80% of the 1 repetition maximum (1RM) are widely recommended, recent studies have shown that low-load (∼30% 1RM) high-repetition (3 sets of 30-40 repetitions) resistance training can elicit similar muscular hypertrophy. Incidentally, this type of resistance training has gained popularity. In the process of testing this hypothesis in a research study in our laboratory, a subject was diagnosed with exertional rhabdomyolysis after completing a resistance training session that involved 3 sets to failure at 30% 1RM. Reviewed were the events leading up to and throughout the diagnosis of exertional rhabdomyolysis in a healthy recreationally-trained 21-year-old woman who was enrolled in a study that compared the acute effects of high-load low-repetition vs. low-load high-repetition resistance training. The subject completed a total of 143 repetitions of the bilateral dumbbell biceps curl exercise. Three days after exercise, she reported excessive muscle soreness and swelling and sought medical attention. She was briefly hospitalized and then discharged with instructions to take acetaminophen for soreness, drink plenty of water, rest, and monitor her creatine kinase (CK) concentrations. Changes in the subject's CK concentrations, ultrasound-determined muscle thickness, and echo intensity monitored over a 14-day period are reported. This case illustrates the potential risk of developing exertional rhabdomyolysis after a low-load high-repetition resistance training session in healthy, young, recreationally-trained women. The fact that exertional rhabdomyolysis is a possible outcome may warrant caution when prescribing this type of resistance exercise.

Ultrasound Findings of Delayed-Onset Muscle Soreness

The purpose of this series was to retrospectively characterize the ultrasound findings of delayed-onset muscle soreness (DOMS). The Institutional Review Board approved our study, and informed consent was waived. A retrospective search of radiology reports using the key phrase "delayed-onset muscle soreness" and key word "DOMS" from 2001 to 2015 and teaching files was completed to identify cases. The sonograms were reviewed by 3 fellowship-trained musculoskeletal radiologists by consensus. Sonograms were retrospectively characterized with respect to echogenicity (hypoechoic, isoechoic, or hyperechoic), distribution of muscle involvement, and intramuscular pattern (focal versus diffuse and well defined versus poorly defined). Images were also reviewed for muscle enlargement, fluid collection, muscle fiber disruption, and increased flow on color or power Doppler imaging. There were a total of 6 patients identified (5 male and 1 female). The average age was 22 years (range, 7-44 years). Of the 6 patients, there were a total of 11 affected muscles in 7 extremities (1 bilateral case). The involved muscles were in the upper extremity: triceps brachii in 27% (3 of 11), biceps brachii in 18% (2 of 11), brachialis in 18% (2 of 11), brachioradialis in 18% (2 of 11), infraspinatus in 9% (1 of 11), and deltoid in 9% (1 of 11). On ultrasound imaging, the abnormal muscle was hyperechoic in 100% (11 of 11), well defined in 73% (8 of 11), poorly defined in 27% (3 of 11), diffuse in 73% (8 of 11), and focal in 27% (3 of 11). Increased muscle size was found in 82% (9 of 11) and minimal hyperemia in 87.5% (7 of 8). The ultrasound findings of DOMS include hyperechoic involvement of an upper extremity muscle, most commonly appearing well defined and diffuse with increased muscle size and minimal hyperemia.

Effect of manual lymph drainage on removal of blood lactate after submaximal exercise

[Purpose] It has been well-established that exercise-induced muscle damage occurs following intense exercise. Massage is commonly used to manage muscle damage resulting from exercise. However the effect of massage after exercise is still not clear. The purpose of this study was to examine the effect of manual lymph drainage on muscle damage and on the removal of blood lactate following submaximal exercise (SE), as part of a solution to the challenging problem in sports medicine of muscular recovery after exercise. [Subjects and Methods] Eighteen healthy male students, with moderate exercise training, were randomly assigned to either receive manual lymph drainage (MLD) or serve as controls. Both groups were subjected to a graded exercise test, performed on a treadmill ergometer, to determine each subject's individual anaerobic threshold (IAT). Seven days later, all subjects were made to run for 30 minutes on the same treadmill ergometer, at a running speed equivalent to the IAT. One group received MLD treatment, while the control subjects received no treatment. [Results] Following an increase immediately after exercise, lactic acid (LA) and lactate dehydrogenase (LDH) serum levels dropped rapidly and significantly at the end of MLD application and two hours after SE in the subjects receiving MLD. The course of creatine kinase (CK) and myoglobin levels was comparable, and with myoglobin showing a significant difference at 2 h after SE, and CK at 24 h after SE. [Conclusion] Manual lymph drainage after SE correlated with a more rapid fall in LA and of the muscular enzymes of LDH, CK and myoglobin, and may have resulted in an improvement in the regenerative processes elicted by structural damage to the muscle cells.

Exertional rhabdomyolysis of the elbow flexor muscles from weight lifting

Ultrasound imaging of rhabdomyolysis previously has been reported in the literature, but differing descriptions of its appearance exist. In this report, we describe a relatively rare case of exertional rhabdomyolysis of the anterior arm muscles. This injury may appear sonographically different than more severe cases of rhabdomyolysis. Our patient was a young, active individual participating in a weight-lifting exercise as part of a physiology laboratory experiment. Ultrasound was helpful to assist in the diagnosis and rule out other conditions. He was treated conservatively and eventually made a complete recovery.

Ultrasound of skeletal muscle injury: an update

Muscle injury is one of the most common sports-related injuries. Ultrasound and magnetic resonance imaging (MRI) are the most useful imaging techniques for assessing muscle injuries. Ultrasound generates images of a greater spatial resolution than MRI; it allows real-time functional and dynamic assessment of muscles and tendons. It combines this information with physiological assessment of blood flow, is well tolerated, noninvasive, and cost-effective. Conversely, its soft-tissue contrast is not as good as MRI. Muscle injuries are conventionally separated into acute and chronic. This article reviews the spectrum of muscle injury and highlights the role ultrasound plays in providing specific diagnostic and therapeutic answers.

Relationship between serum creatine kinase activity following exercise-induced muscle damage and muscle fibre composition

In this study, we examined the relationship between serum creatine kinase activity following exercise-induced muscle damage and muscle fibre composition. Seventeen untrained males volunteered and underwent a .[Vdot]O2max test, Wingate test, and an exercise-induced muscle damage protocol. Muscle soreness and blood samples were recorded before, immediately after, and 24, 48, 72, and 96 h after exercise. Biopsy samples from the vastus lateralis were collected one week after exercise-induced muscle damage and were assessed for muscle fibre composition. There was no significant relationship (P > 0.05) between muscle fibre composition and creatine kinase activity. A significant positive correlation (P < 0.05) was observed between soreness 48 h after exercise and type II and IIb fibres, and a significant negative correlation (P < 0.05) was observed between soreness 48 h after exercise and type I muscle fibres. Significant positive correlations were observed between soreness 48 h after exercise and the fatigue index, relative average power, and relative anaerobic capacity. Our results suggest that creatine kinase activity following exercise-induced muscle damage may not be related to muscle fibre proportions, and higher post-exercise muscular pain may be related to a predominance of type II muscle fibres and higher anaerobic capabilities.

Between-day repeatability and symmetry of multifidus cross-sectional area measured using ultrasound imaging

STUDY DESIGN

Prospective test-retest, intrarater reliability study.

OBJECTIVES

To estimate the intrarater reliability, asymmetry, and associated error with measurement of the cross-sectional area (CSA) of the bilateral S1 multifidi when measured by a physical therapist following a short course of self-directed training in ultrasound imaging.

BACKGROUND

There is increasing interest in the assessment of the lumbar multifidus during the recovery from low back injury. It is important to know the error associated with the CSA measurements obtained by a physical therapist with limited experience in ultrasound imaging when using a portable unit.

METHODS AND MEASURES

Thirty healthy females (mean +/- SD age, 23 +/- 2 years; mean +/- SD mass, 63.1 +/- 9.2 kg; mean +/- SD height, 1.63 +/- 0.06 m) participated. Fourteen subjects returned within 1 to 4 days for repeated measurements.

RESULTS

For all 30 subjects, the average (+/- SD) CSA of the left S1 multifidus (4.18 +/- 0.55 cm2) was larger (P<.05) than the right (4.11 +/- 0.57 cm2), with a standard error of the measurement (SEM) of 0.13 cm2 and average +/- SD asymmetry of 3.5% +/- 3.4%. For a subset of 14 subjects, the between-day intrarater reliability for the right S1 multifidus muscle was ICC3,1 = 0.80 (95% CI, 0.49-0.93), while the ICC for the left side was 0.72 (95% CI, 0.34-0.90). The day-to-day average differences for the left and right side were 0.02 cm2 and 0.04 cm2, respectively. For the most conservative estimate, the between-day SEM was 0.37cm2.

CONCLUSIONS

A physical therapist, newly trained in ultrasound imaging, obtained reasonable between-day intrarater reliability when imaging the S1 multifidus. A high degree of symmetry was found between the bilateral S1 multifidi in a sample of healthy subjects, which is consistent with previous reports from measurements by skilled ultrasonographers.

Delayed-onset muscle soreness does not reflect the magnitude of eccentric exercise-induced muscle damage

This study investigated the relationship between delayed-onset muscle soreness and other indicators of muscle damage following eccentric exercise. Male students (n = 110) performed 12 (12ECC), 24 (24ECC), or 60 maximal eccentric actions of the elbow flexors (60ECC). Maximal isometric force, relaxed and flexed elbow joint angles, upper arm circumference, and plasma creatine kinase activity were assessed immediately before and after, and for 4 days after exercise. Muscle soreness (SOR) was evaluated by a visual analog scale (a 50-mm line, 0: no pain, 50: extremely painful) when the elbow flexors were palpated (SOR-Pal), flexed (SOR-Flx) and stretched (SOR-Ext). Although 24ECC and 60ECC resulted in significantly (P <; 0.05) larger changes in all indicators and slower recovery compared to 12ECC, no significant differences were evident for SOR-Pal and SOR-Flx between 12ECC and 24ECC, or 12ECC and 60ECC. In contrast, SOR-Ext was significantly (P <; 0.05) lower for 12ECC compared to 24ECC and 60ECC. A Pearson product-moment correlation showed SOR-Pal did not correlate significantly with any indicators, however, SOR-Ext and SOR-Flx showed weak (r <; 0.32) but significant (P <; 0.05) correlations with other indicators. Because of generally poor correlations between DOMS and other indicators, we conclude that use of DOMS is a poor reflector of eccentric exercise-induced muscle damage and inflammation, and changes in indirect markers of muscle damage and inflammation are not necessarily accompanied with DOMS.