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4 technologies to enhance sporting performance

Douglas Powell
Douglas Powell
Director of the Breast Biomechanics Research Center (BBRC) in the College of Health Sciences at the University of Memphis
Donghee Son
Donghee Son
Professor in the School of Electronic and Electrical Engineering at Sungkyunkwan University (South Korea)
Mikyung Shin
Mikyung Shin
Associate professor in the Department of Biomedical Engineering at Sungkyunkwan University (South Korea)
Hailey Fong
Hailey Fong
Researcher at Breast Biomechanics Research Center de l'Université de Memphis (États-Unis)
Jean-Christophe Géminard
Jean-Christophe Géminard
CNRS research director at the Physics Laboratory (ENS Lyon)
Key takeaways
  • A number of technologies are being developed around the world to enhance sporting performance.
  • Research has shown that a good sports bra is important for supporting the breasts and demonstrated how it affects the knee joint during running.
  • The work proves that sports bras, which have changed little over the last 50 years, should be considered as sports equipment in their own right.
  • Insoles fitted with sensors could be used to measure the progress and performance of athletes during various sporting activities.
  • Korean researchers have developed a conductive hydrogel capable of regenerating and reconnecting injured muscle to the nervous system.
  • These and other technologies being developed could help athletes progress and improve their performance.

#1 A good sports bra can increase running performance by 7%

As well as a good pair of run­ning shoes, a well-fit­ting sports bra that effi­cient­ly sup­ports the breasts is impor­tant for female run­ners. It can help reduce breast pain and improve per­for­mance. When the breasts are not prop­er­ly sup­port­ed, the body com­pen­sates by pro­tect­ing them in oth­er ways. This com­pen­sa­tion can reduce run­ning per­for­mance, increase the risk of injury and even lead to back and chest pain.

To bet­ter under­stand the role of a good sports bra on the bio­me­chan­ics of run­ning, a team of researchers led by Dou­glas Pow­ell and Hai­ley Fong from the Breast Bio­me­chan­ics Research Cen­ter at the Uni­ver­si­ty of Mem­phis (USA) stud­ied how wear­ing a bra impacts knee joint stiff­ness dur­ing exer­cise. This bio­me­chan­i­cal mea­sure­ment pro­vides infor­ma­tion on the resis­tance of the knee joint to an applied force. To do this, the researchers recruit­ed 12 non-pro­fes­sion­al female run­ners aged 18–35 and had them wear two dif­fer­ent sports bras: one with high sup­port and the oth­er with low sup­port. A con­trol group did not wear a bra at all.

Each par­tic­i­pant ran on a tread­mill equipped with force detec­tors for three min­utes. The researchers filmed the run­ners using a 10-cam­era motion cap­ture sys­tem. Retrore­flec­tive mark­ers placed on the run­ners’ bod­ies also tracked their move­ments. The researchers then used soft­ware that they had spe­cial­ly devel­oped in this work to cal­cu­late the excur­sions of the knee joint (flex­ions, exten­sions and rota­tions) on the basis of the images they obtained. They also mon­i­tored chest move­ment dur­ing the exercise.

The exper­i­ments revealed that when breast sup­port was high­er, the knee joint was more rigid, thanks to small­er joint excur­sions. Com­pared with the con­trol group, the low- and high-con­tain­ment bras increased knee joint stiff­ness by 2% and 5% respec­tive­ly. Over­all, a high sup­port sports bra appeared to improve run­ning per­for­mance by 7%. The research also revealed that improve­ments in run­ning per­for­mance with high sup­port sports bras was strong­ly cor­re­lat­ed with breast size: women with larg­er breasts ben­e­fit­ed more in terms of run­ning performance.

Over the last 50 years, bra design has changed lit­tle, explains Dou­glas Pow­ell: “our results, com­bined with those of pre­vi­ous stud­ies, show that sports bras should be con­sid­ered not just as appar­el, but as sports equip­ment in their own right.”12.

#2 3D-printed insoles to assess athletes’ performance

In top-lev­el sport, a frac­tion of a sec­ond can make all the dif­fer­ence. Made-to-mea­sure insoles can improve sport­ing per­for­mance and researchers at Empa, ETH Zurich and EPFL, all in Switzer­land, have devel­oped a device that is much more sophis­ti­cat­ed than a sim­ple insert. The new insole com­pris­es pres­sure and shear sen­sors that can mea­sure these para­me­ters direct­ly on the sole of the foot dur­ing any type of phys­i­cal activity.

“The pres­sures record­ed can be used to deter­mine whether a per­son is walk­ing, run­ning, or climb­ing stairs. It’s even pos­si­ble to deter­mine whether they’re car­ry­ing a heavy load on their back, in which case the pres­sure shifts more towards the heel,” explains Gilber­to Siqueira, project leader and researcher at Empa and ETH’s Com­plex Mate­ri­als Laboratory.

The soles were fab­ri­cat­ed using a 3D print­er, known as an extrud­er. The base of the sole is made from a mix­ture of sil­i­cone and cel­lu­lose nanopar­ti­cles. A con­duc­tive ink con­tain­ing sil­ver is then print­ed atop this first lay­er. The sen­sors, which are piezo­elec­tric, con­vert mechan­i­cal pres­sure into elec­tri­cal sig­nals. These are print­ed on the con­duct­ing part of the sole, where the pres­sure exert­ed by the foot is great­est. The ensem­ble is pro­tect­ed by a final lay­er of sil­i­cone. An inter­face for read­ing the sig­nals gen­er­at­ed, insert­ed into the sole, com­pletes the device.

As well as Empa, ETH Zurich and EPFL, the Cen­tre Hos­pi­tal­ier Uni­ver­si­taire Vau­dois (CHUV) and the ortho­pe­dics com­pa­ny Numo were also involved in this work. Such insoles could be used by ath­letes to mea­sure their progress dur­ing train­ing and their per­for­mance in gen­er­al3.

#3 An electrically conductive hydrogel could help regenerate muscle

Researchers at the Insti­tute of Basic Sci­ence (IBS) in South Korea have devel­oped a new tis­sue pros­the­sis made from a con­duc­tive hydro­gel that can be inject­ed direct­ly into an injured mus­cle to regen­er­ate it and recon­nect it to the ner­vous sys­tem. This pros­the­sis has enabled rats with torn hind limbs to walk again.

Mus­cle injuries such as strains or tears are com­mon sports injuries. When a mus­cle is torn, its elec­tri­cal com­mu­ni­ca­tion with the ner­vous sys­tem is dis­rupt­ed and it no longer func­tions prop­er­ly. Today, these injuries can be treat­ed using portable or implantable elec­tron­ic devices. How­ev­er, these devices are rigid and inflex­i­ble, which makes them incom­pat­i­ble with soft bio­log­i­cal tis­sue. Not only are these devices uncom­fort­able for the patient, they can even cause inflam­ma­tion, which slows the heal­ing process.

The researchers’ flex­i­ble pros­the­sis com­pris­es a hydro­gel con­tain­ing hyaluron­ic acid – a nat­ur­al poly­sac­cha­ride with mechan­i­cal prop­er­ties sim­i­lar to those of soft tis­sue and known for its regen­er­a­tive prop­er­ties. To make the pros­the­sis elec­tri­cal­ly con­duct­ing, they added, via cova­lent bonds, chem­i­cal com­pounds to it con­tain­ing hexag­o­nal rings that can accom­mo­date gold nanopar­ti­cles. Gold is also bio­com­pat­i­ble and intrin­si­cal­ly chem­i­cal­ly inert.

When the gel is inject­ed into the mus­cle tis­sue of a rat, the chem­i­cal bonds it con­tains are bro­ken. They quick­ly re-form once the hydro­gel is fixed in the mus­cle, how­ev­er. It is this inno­v­a­tive chem­istry that enables it to regen­er­ate dam­aged tis­sue. What is more, the gel does not over­ac­ti­vate the animal’s immune sys­tem. It there­fore does not pro­duce fibrous scar tis­sue, as can be the case with con­ven­tion­al implantable prostheses.

The researchers found that the hydro­gel adheres to the periph­er­al nerves of the injured mus­cles in the rat’s hind leg. This means that the device can be con­nect­ed to elec­tri­cal wires and the sci­en­tists are able to acti­vate the mus­cle by send­ing elec­tri­cal stim­u­la­tion through the gel. Repeat­ed stim­u­la­tion enabled the rodents to walk short­ly after an injury.

Ulti­mate­ly, the researchers would like to apply their tech­nique to human mus­cle. How­ev­er, before they can do this, they will need to car­ry out stud­ies on ani­mals larg­er than rodents to deter­mine whether the hydro­gel can con­duct elec­tric­i­ty over longer dis­tances4.

#4 Analysing how a table tennis ball bounces off a racket

Researchers in France have mea­sured the speed of pro­gres­sion, rota­tion and rebound angle of a table ten­nis ball off a glass sur­face. Led by Jean-Christophe Gémi­nard, CNRS research direc­tor at the physics lab­o­ra­to­ry of the ENS in Lyon, the sci­en­tists fired the ball onto a glass plate while vary­ing the angle and impact speed of the ball. They then mea­sured the above para­me­ters by analysing videos of how the ball inter­act­ed with the plate.

The result: at angles of inci­dence typ­i­cal­ly less than 45 degrees, the ball rolled (with­out slid­ing along the sur­face of the plate) com­plet­ing a frac­tion of a full turn, that is, less than one turn, before rebound­ing. At high­er angles of inci­dence, the ball still slid as it left the sur­face, reduc­ing its rota­tion after the bounce. The researchers explain that when bounc­ing off a sol­id sur­face, such as a glass plate, the final rota­tion, speed and bounce angle of the ball are gov­erned sole­ly by the fric­tion between the ball and the sur­face. This result, they say, would be the same for a ball bounc­ing off a real ping-pong table.

To make their exper­i­ments more real­is­tic, Jean-Christophe Gémi­nard and his col­leagues then repeat­ed them using a rack­et cov­ered with a stack of foam and elas­tomer. To a cer­tain extent, this sce­nario pre­vent­ed the ball from slid­ing over the sur­face of the glass plate. Play­ers capa­ble of repro­duc­ing the tech­niques described in this study will undoubt­ed­ly have a sig­nif­i­cant advan­tage, say the researchers.

Final­ly, the sci­en­tists repro­duced their exper­i­ments on sur­faces com­mon­ly used by table-ten­nis play­ers in the real world, but to date the results of this part of their work have not yet been made pub­lic56.

Isabelle Dumé

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